This is more simple than is being made. If there are no markings, it is not a trench gun. I hear this story all the time. People look at things like this and try to justify it in any way. I'm not saying that's what's happening here from the buyer, but the sellers are usually the worst perpetrators of this. When a gun was brought into service, off the shelf of a store or from the factory, they were marked. I've seen countless cobbled together guns and heard every story you can imagine. I'm glad he came here to ask the questions. Nothing worse than dropping that kind of money finding out you got duped.