Thank you both for your help. I will post some photos soon.
The photos of the "Kentucky Flintlock" you linked look remarkably like my pistol, with some exceptions (percussion cap v. flintlock). Both are engraved "J. Bishop" on the lock, and both have very similar decorative engraving on lock and trigger guard.
The linked article does not explain why or how they think that pistol is "Kentucky". Mine has "London" on the barrel, but I suppose the barrel and/or lock could have been made in England and shipped to America.