Thankee for the kind words, Jim. I feel like writing a headline: "Pundits Astounded as Military History Degree Actually Proves Somewhat Useful"
To respond, I had my misgivings about what is left of the lock from the outset. The sans-serif numerals certainly didn't seem right; no specimen of British lock I've ever seen (in my, I should add, very limited experience) from that period had sans-serif numbers or letters, and
this page here gave my suspicions a boost. Likewise, the lack of a border around the lockplate (which as I understand it was pretty much de rigeur on British locks) and absence of any visible proof markings seem indicative of a fake. I've very gently removed some of the lockplate rust with a soft cloth and WD40, and apart from another "8", stamped just below the former location of the nipple, can see nothing more than what I've described above. On better examination, the lion seems what I can only call ragged; it doesn't quite match up to illustrations and photographs I have seen of the EIC lion, and seems more crudely inscribed.
Regarding provenance, I had a quick phone conversation with the donor on Friday and gleaned that he had good reason to believe it to be genuine, and that its condition was probably the result of spending some time in his garage; the British climate has struck again. It's rather unfortunate, but what little he could tell me led me to the same conclusion as you - that this particular piece was produced in a location such as Darra, perhaps as a functional weapon, but not as long ago as the lockplate rather optimistically claims. He also said that the weapon has been in this country for between 10 and 15 years, at least. I'm afraid I can't give any more detail than that.
My own particular theory - if you'll excuse my boldness - is that this gun, perhaps, was assembled relatively recently; certainly within the last century or so. I'm going to go out on a limb, and suggest that the barrel may be rather older than the lock. The lock itself, I'd guess, was either made to fool a foreign buyer into thinking it had been captured from a converted European flintlock (e.g. a Pattern III Brown Bess), or perhaps stamped with these markings at a later date than its original manufacture, for the same purpose. Would an Afghan/Khyber gunsmith bother with such things if he were selling the weapon to one of his own kind? I understand the Darra chaps still put so much store by the stamp "V.R" that, on occasion, one can find guns stamped with the V.R. cypher that also say they were made in 1952!
Ward, I'll try to get some better pictures of the lock as soon as possible (and likewise of the rest of the gun). It may take some time as I work out how to use that infernal digicam, but I will, eventually, master it! Hopefully, anyway. Regarding treatment: by "pull" the barrel, I take it you mean dismount it from the furniture? I'm afraid I can't do that; in no sense am I even remotely qualified to dismantle a gun, at least, not if there's to be any hope of its re-assembly. I've already rigged up a home-made ramrod, with an auger (well, sawn-off corkscrew) superglued into a hole at one end, but attempts to get the steel corkscrew into whatever's down there have produced only corrosion stuck to the thread. As I understand it, this could mean a couple of things; it's possible that the de-activation was doubly ensured by pouring iron or steel down the barrel (although if so, how my paperclip is penetrating the touch-hole seems a bit of a mystery), but I'm told that Afghan fighters would put an awful lot of things down a Jezail; anything from lead balls to copper telephone wires hammered into slugs. If that is the case, I wonder if they might have used an iron ball. Not good for the gun, of course, but still.