A couple of other things to possibly consider.

Rib engraving does not match the receiver engraving at the breech face in fit and style.

Lock engraving is different style than receiver engraving.

Does rib scroll somewhat match the lock scroll ?

Were barrels reproofed from 14 ga. to 13 ga. at the time of conversion. I'd think this was a normal thing. ?

From the photos, I don't see a serial number on the receiver.

Questions ? Are the barrels and locks from a different source than the receiver ?

http://www.bakercollectors.com/