Could have been rebarreled at some point. That might explain the different things you noted. Many guns were returned to the maker or another gunsmith to have a new set of barrels made. Then they would be sent out for proof. Rib address would be current location at the time unless requested otherwise. Trigger guard could have been replaced another time. If done by the maker I would expect a matching number so it had to be a take off. A cheap repair using parts on hand.
Makes sense, although Nick's answer is also a possibility. Thanks to both of you for providing an answer.
