I have a Winchester Model 12 Riot Gun, not trench gun. Bought it from an Air Force officer many years ago at nearby Scott Air Force Base. He bought it directly from the US Air Force when he was stationed in Germany. It had been re finished by a military arsenal at some time. Different serial numbers on the action and the barrel. US and flaming bomb on the metal. Unfortunately in several moves he had lost the original paperwork from when he bought it. I have no reason not to believe the story but also no way to prove it. Don't remember what I paid for it at the time. Think possibly around $200 and it was probably 20 or 25 years back. It supports what has been said here about mis matched guns. Metal is parkerized by the way.