I was watching the old Steve McQueen movie today, "Nevada Smith" and near the start of the movie he has what appears to be an over/under percussion muzzleloader. The gun appears to be a drilling and looks like it has a rifle barrel over a shotgun barrel. There also appears to be two "tubes" on each side between the barrels, possibly for the ramrods? I checked the Internet movie Firearms Database to see what it was but the movie isn't listed except for one entry under Steve McQueen with no link that only IDs a Single Action Army for "Nevada Smith". Attached are a couple of screen captures with the gun. Anybody have an idea what it is?...