Apologies for the late reply, the sword has been in transit and I figured there was no point in making multiple posts if it can be avoided. Will attempt to take acceptable photos later but a quick update first:
As above, it has arrived. I would congratulate Bonhams on using a deceptively fine camera lens. Photos appear as if the guard is quite large. That is not the case whatsoever. The guard is extremely form fitting, like a British Scots field officer's sword (a bit of foreshadowing). It is of a non ferrous metal, so their description of a 'silver' hilt may actually be true.
The nut at the top, almost like an old top as in the toy, is threaded. I was able to unscrew it with absolute ease. The bow of the guard is secured a la most sabres to the pommel cap underneath. Whatever metal the guard is made out of has mild flex but I'm not going to do anything severe enough to attempt to fully disassemble it. However, I would guess that the knucklebow, like a Wilkinson, is already secured to the blade, perhaps by a 2nd hidden nut? The pommel cap is set somewhat asymmetrically to fit on the grip and tang. What this means I cannot say but when looking perpendicularly down at the pommel, the center is off by a few mm. Perhaps a way of taking a curved tang off center and doing what you can?
The stats are as follows, from a rough bed estimate:
-Weight == ~775grams, give or take some due to the extreme length and balance
-Blade length == ~85cm, but with a rounded tip that looks quite weathered it may easily have been 86cm back in the day
-Width/thickness == 30mm wide which seems to be exactly where I would assume, but only about 7-8mm thick. I suppose this is consistent with earlier blades, however it may have been a bit wider as heavy grinding marks are observed on the ricasso and the spine.
-Both the spine and the ricasso are angled to form narrow slightly undulating ridges. As this is outside of my general area and god knows I cant afford early 18 or before at this point, I will photograph it later and leave discussion to you all.
I was unable to find any markings whatsoever. Over the ~300 years since the blade was made, it appears to have gone from a flattened hexagonal-to-lenticular profile into a more lentincular one. The engraving is the same on both sides, and you can faintly see those period-appropriate decorations below the fullers. I cannot fully make out the engravings myself but I trust what has already been posted, perhaps combining both sides will make it easier?
As I said above, the hilt is much smaller than photos made it out to be. Fortunately, what I perceived as a round bulbous thing meant only to be hammer gripped is actually quite pleasant in the hand. No curve, but closer to the french 1845/55. Feels quite nice and one can index their thumb on the back nicely. I cannot execute a fully extended Radaelli type grip, but it feels better than most 'spadroon' grips that the north and western Europeans used at this time.
How it feels in the hand? I had initially thought that this was a broadsword, quite literally, based on the images. However, when moving the sword around, it feels closer to what I would consider a shearing sword or thrust-centric backsword. The foible has flex, but is still quite sharp. POB is not far enough down the blade nor is it wide enough to be a hugely effective cutter, although wrist-articulated actions would at least do serious damage to any unarmoured limbs. The spine stays thick or at least flat-ter than the front only to the edge of the double fullered engraved forte, upon which it becomes as sharp as the front. Maybe not a truly symmetric double edged sword, but let's call it 87.5% of the way there?
If you've ever handled a Scots Field officer's sword before, or even the French superior officer's sword, this feels extremely similar. Quite similar to a Spanish-influenced Neapolitan sword I have and wrote about on the SBG forum and is my favorite non-sabre sword of this era even. Like that, there is a certain liveliness to it. Similar to a spadroon but my primary issue with at least the British/German/Swedish styles is those grips are so narrow, with vestigial finger rings, that even if you wanted to cut it is all but impossible to hold them nicely. That is not the case here. It is not optimized for thrusting in that there is anywhere to pinch or finger the guard, but it is a much more neutrally designed grip you can hammer or handshake with equal success.
Whatever the Grenades are made of is the same material as the bars of the guard. The grip was once lacquered as evidenced by remains of black intermittently. Silver wire twist in the grooves. Blade is a bit bent and I may attempt to alleviate that later. A more post-Napoleonic black leather washer a la the French sits at the ricasso. Very thin and a bit rubbery, I have not yet attempted to remove it to see what is underneath but it is <1mm so there are no markings. The shape of the main guard does remind me of this sword here:
https://sallyantiques.co.uk/product/...-hilted-sword/ (Please let me know if this should be removed, it has already sold, I am only posting it for reference), with a similar curve of the tail, the boat shaped main section, and the way the bars of the guard extend from it.
Any possible provenance that is mine to guess would probably be a senior officer either mounted or dismounted, but leading a non-mounted unit given it is not as robust as most cavalry sabres are, but that is based solely on my experience with British and French superior officer sabres, which are quite lovely things. Ironic to lock away a very well balanced svelte thrust-and-cut sword behind a rank at which you are unlikely to ever use it.
All of that to say I still have no damned idea what it is. I've gone through all 77 pages of prior threads to open everything I find interesting and am still working my way through those. I am fully open to the idea of it being French or anything else. However, I was under the impression that this specific type of grip and pommel cap was for the Spanish, Mexican, colonial, post Colonial, etc. sphere of Latin America, and I would be curious to see other designs. I buy swords as mechanical pieces of history though, not for the story, so it ultimately matters not where it originated from, only that I can find an answer.
I will attempt to take photos later tonight and do more precise markings. Because the tang is threaded (which I'd frankly date to no earlier than the 2nd quarter of the 19th century IE 1825-1850), the sword is in quite solid condition. A bit of play wrt the pommel cap and the shrunken horn grip, but the remains of the lacquer could also be former leather that has worn and caused the rattle as well.
Profuse apologies for rambling for so long, I simply wanted to make sure I covered every point I could think of. If there are any requests for photos, please let me know. I will probably take some comparing it to various British and French and Spanish/Neapolitan swords I own as well. Thank you!