Sorry about the pictures, no idea why they didn't come through. There are no diamonds that I see.
Beside the stamped numbers is a 5 point star, a few letters here and there.
The one outstanding mark is the Triangle, with the Circle inside of it and the Capital T inside the circle. This stamp is located on the top of both barrels near the breech. There is alot of scroll work on this shotgun around the side plates, the barrel breech and the bottom of the receiver. It would seem from this work it was not a cheap gun. The stocks are in bad shape, but they have checking on the fore stock and at the hand grip, which is more rounded like a pistal handle than flat like most hand grips on todays guns.