Well there was a small chance that it might be the remains of, but a few seconds after unwrapping it, it was pretty obvious it wasn't.
What it is is a cheaply made "trade" pistol with poor quality lock.
The stock cracked through in several places and while it has a new forend it's not even glued in place. New pins are driven in from one side only rather than through. If only they'd left it as was then I'm sure it could have been repaired decently.
The flat faced unbridled lock appears right for the circa 1770 variation, excepting there's no internal bridle (cheap trade) and nothing in the way of markings.
The sideplate was obviously mad to take a belt clip and the hole has been tidily filled.
The lock mortise is poorly executed
Not got the barrel off yet due to the pins and appropriate tools being 12 miles away.
Despite all this I may have a cunning plan. Some may agree, others be horrified.
I have in stock an original barrel, a slightly earlier lock (Sea Service ??) and a contemporary drilled sideplate.
What I'd always wanted was to gather together the remaining fittings and carve a new stock to mount them all on.
So donor pistol or not?