Yesterday a coworker brought in an old wall hanger shotgun he wanted to sell and Ive never seen anything like it. It instantly reminded of a springfield trapdoor rifle in that the breach flips open in order to load and eject shells, except this one flips to the side. It has a monster hammer on it bigger than I have seen before. The strange part is there is very little in the may of markings on it. It has an H proof mark on the side of the barrel next to the receiver, it has 3 proof marks on the top of the breach that I think are YBO but they are extremely hard to read. and the Y is above the B and the O is lower and to the right. The final marking is a 1988 underneath the breach and that is all it has for markings. Anyone have any idea what it is