Pete, I think the horse, not the Indian, is the likely villain in this story. I have some friends that do horse pack in treks, and hunt from horseback. Their guns could be taken to a museum that doesn’t have a firearms expert, and nobody would even question they’re age. One of these old hunters, that is long gone now, said that a horse wrecks a rifle out of awkwardness, but a mule had it planned from the gitgo.
Hungry Horse