Welcome. Now you get to chase down the details. From your pictures it looks to be a sleeved double. If not something you know about that is your first search. Pictures of the underside of the barrels will tell you what shells are appropriate. Before you shoot it do have it inspected by a gunsmith who is well versed in doubles. Don’t shoot Wallyworld shells in it. Condition looks very nice but the devil is in the details and only a inspection will tell you what you need to know. I would have the chamber length checked and the thickness of the barrel walls measured. If they are good, that gun should give you years of recreational shooting fun. It is not built for high volume shooting, like a K80 or PGun, but was made to be a nimble shooting gun, that is easy to carry.