Being involved with my county museum, I can tell you everything that comes through the door, in the way of donations has a story. I can't tell you how many guns are linked by family legend to, either the Revolutionary War, or the Civil War. Most of them are either of the wrong time period, or a very unlikely caliber.
Often valuable weapons were willed from family, friends, of fellow travelers, who perished in route. some times families of young pilgrims, if they had the finances would purchase a fine weapon for the traveler, to the new world. So it isn't entirely impossible that a young cooper could have owned such a weapon. But it is unlikely.
I am reminded of the time I had a friend take me to a cabin in a neighboring community to look at a shotgun he was trying to buy. The gun turned out to be a .20 gauge side by side, that was a total piece of art. Subsequent research tracked it to having been built for a Belgian prince, of duke, or something. This gun was sculpted from butt, to muzzle. It was more a sculpture than a firearm ( the hammers were bird dogs flushing a bird). The woman that owned it, was given it by an elderly friend, so she could shoot the hawks, that were after her chickens. She quit using it because she couldn't afford shells for it.
So, you never know how somebody comes by a fancy firearm.
Hungry Horse