Thank-you for the info; I know nothing about military history in any of its manifestations.
I do know that if, while possibly engaged, I was choosing between a typical smallsword - be it colichemarde or not - or this sword of mine, I would not hesitate to choose the latter.
These early Shotley Bridge smallswords that I have are a perfect example of this weapon, even though they were forged in 1687/8. That said, I am now fully convinced this sword of mine is in fact a smallsword, and I don't know why I didn't assume that from the start.
With regard to the colichemarde grooves, my thinking has been this: according to the various professors of engineering at my local universities, a groove of this type would be more difficult to hand fashion than the typical hollow, so consequently, "why bother". Unless the weight and stiffness of the blade on a colichemarde is improved by the groove, which is possible. There is a thesis by a fellow member of the Arms and Armour Society, Maciej Pulaczewski, that may interest you. I can email you a pdf, it is an exemplary work.
ps. the blade length of my 'possible 1767 sword' is 34 inches (87cms) which puts it beyond the majority of smallswords by a significant margin including the maximum 1786 pattern of 78cms.