Sorry to leave you hanging for the day.
Its a 20ga on a XX frame with damascus barrels. I could imagine a "re-gauged" if you told me 16ga were built on the XX frame. They were right?
Also, i could believe rebarreled if it currently sported steel barrels. Rebarreled to damascus?
Dolls head fit perfectly. I would call it on the heavier side with barrels and forend weighing just over 3lbs.
Intrrestingly enough the barrels are each stamped with different serial numbers that are off by one. Looked to be stamped by same tools.