If I remember right, touch hole liners go back to the 1600's. In 18th century America they were used pretty commonly as a repair for burned out direct drilled vents. Wouldn't be at all out of place on an 18th century American rifle that had seen some use.
If somebody ddn't want to use stainless which would be understandable in certain cases there are other options.
If somebody ddn't want to use stainless which would be understandable in certain cases there are other options.