Different material but the same story. I have a flintlock rifle with a barrel from one of the best rifle barrel builders that has ever been. He signed his name, W. M. Large, with stamps in a semicircle on the side flat of the barrel. On my barrel the G in Large is backwards, this has never been seen on any of his barrels.
When I showed picture of his stamp on M/L sites some claimed my barrel was a fake. Fortunately there was a guy on the site who worked with Mr Large in the 50s making barrels. I had an endoscope picture inside the barrel, Bob Roller took on look at the rifling configuration and said "that is one of Bill's barrels".