Swinney's "The New York State Firearms Trade" books in Vol.I, pp.304, 305, has a large write-up on James Buswell, over a full page, mostly from census data and a couple of local history books. Interestingly, Swinney lists 4 previously known Buswell rifles, but none seem to be of the quality of the gun you are looking at. Of course, Swinney didn't get into gun values. Probably have to locate a NY collector to get an idea, of keep an eye on GunBroker.
Shelby Gallien