Hi Richard,
Yes, Verncombe of Bristol. Mike Brooks likely is correct that maple wood from America could find its way into the British gun trade. However, there were also quite a few excellent American gun makers who clearly understood British styling. When I was doing research for my recent militia musket project, I was hoping to find examples of colonial manufacture that closely resembled the Brown Bess. I did not have to search very hard for very good examples. In the process I also examined fowlers that were modified for military use. Some were very good examples of British styling in almost all details. Watkeys of New York, Annelly of New York and Trenton, NJ, Nicholson of Philadelphia, and Doud and Norton of Goshen, CT. Any of those makers could have made the gun we are discussing. Goshen was a gun making center that deserves a lot more research given the number of makers working there including the Hills family.
dave