Your gun has early (pre 1904) Birmingham black powder proofs. The rod going through the front lump indicates it's of the facile princeps design, not the A&D design (the two can look identical from the outside). Both bbls had some degree of choke. The 12 over 30 on the bbls puzzles me. 12 is obviously the nominal bore but 30 is a mystery. Never seen one like that. May have something to do with the brass cases. If it is chambered for brass, the chambers will be too tight for a regular 12 ga shell.
It occurrs to me that 30 grams is just over 1 oz so this gun may have been reproofed on the continent at some time, the marks 12 and 30 having been added. I can't read the symbol nearest the muzzle, but it shouldn't be there I don't think.
The gun has damascus bbls that were proofed at .751 bore (11 bore).
Looks like the stock has been off (screws on the safety are not timed), probably for a refinish at some time.
