There is an illustration of an 18th century coning tool in the fine book "The Gunsmith of Grenville County" by Peter A. Alexander. You could probably make this tool for yourself. Start a little cottage business doing PC/HC touch-holes...
As Mr. Alexander says in his description of the operation and effectiveness of this tool, "This should last for a lot of shooting, but eventually the touch-hole will open up, so you do exactly what gunsmiths did in the 18th century -- install a touch-hole insert. Touch-hole inserts, historically speaking, say that the gun has been used for a god long time before being repaired. To see one on a brand new rifle would be strange."
So, I guess it would be how your firearm is being presented. Are you building a brand new gun to look like a brand new gun, or is it supposed to look like it's spent many moons on the trail harvesting game and warding off adversaries?
PC/HC-wise there's no shame in having a liner in your barrel, unless it's a brand new looking gun that shouldn't show repairs