I found what I suspect to be a trade rifle butt plate.....or maybe not. The location is certainly right but I'm not sure on the rest. Any ideas? It could be something completely different....not sure. It's 5 3/4" long.
Also could be a shotgun or musket butt plate. It has two screw holes, and lots (not all) trade muskets had the butt plate nailed on. It doesn't look like a trade rifle butt plate to me.