Chapin is a known gunsmith. I don’t recall hearing of guns marked by him that were rifles. One of the tradegun books has an extremely long smoothbore signed by him. I don’t think he was an American gunsmith. In fact I think he made high end fowlers, and chiefs grade trade guns.
The other gun could be a lower end musket, but with no name on it, and no proof marks, it might be an early replica thats had a hard life.
Hungry Horse