Ob, My impression, when looking at your first set of pics was that the gun had some of the features of a pigeon or waterfowl gun with its low hammers and flat file cut rib.Being marked for the 2 3/4" case and having choke in both barrels adds further to that impression. The weight would be another indicator and the drop at comb of the stock. Regarding value, the previous advice of getting the barrel wall thickness measured would be the first step and whether it remains in original black powder proof.I would echo Roys evaluation or a bit more if it was nitro-proofed. Looks like a nice shootable gun. Terry

Better to keep your mouth shut and be thought stupid,than open it and confirm.