My barrels had no liner, but I believe it would be redish color if it was a liner. You could take a wire wheel on a grinder and with a little pressure you will scuff thru the liner.
From what I hear, the liner can make it thru a good fire and still be stuck on pretty good.
For the future, the paint on the outside really doesn't have to come off unless you are doing it for cosmetic reasons. Mine has the original paint with hammered black on top of that. Unless you really crank out a heck of a fire the high heat paint isn't needed. There has been no ill affects on mine. There are pics of mine in my sig line.
Good Luck and don't forget to show us a few pics in progress.