Just a guess, but maybe re-barreled in the US? Barrels look a bit undersized at the breech face, which is the only thing that makes me think the gun has been re-barreled. Could explain the lack of proofs on the barrels.

The quality/style of the engraving is far above anything I have seen on an American made gun. Absolutely beautiful rose and scroll.

It is going to be interesting to see the ideas that people have on this one.

“I left long before daylight, alone but not lonely.”~Gordon Macquarrie