I should say that I have never seen the gun in person, but looking at the pics in RCA think that what looks like relief carving is wire inlay instead. In fact if you look closely at the pictures you can see a lot of wire inlay where there would normally be incised carving.
I've only had about a half dozen Bucks rifles in hand and all have been incised carved, with no relief carving.
Guess I should say never say never, but that's my experience.