Bill, Dr. Gaddy used motor oil or boiled linseed oil on his finished barrels. Heat the barrels lightly and with a small cloth and a few drops of boiled linseed oil put it on and leave it for a day. It gives the barrels a nice hard shiny finish that lasts a long time. He also used logwood chips and boiled the barrels in them to give them a darker finish. Most L.C. Smiths from the factory that had steel barrels had a satin finish on them and I have never seen a set of Damascus or Stub Twist from the factory to know how they looked. I would post some pictures of ones I have done, but Photobucket will not let me post any to a third party site, so I have to find all my pictures and put them on another photo hosting site like jpgbox.
I only finish Damascus and Stub Twist to bring out the highlights and never as bold as some you see because the rest of the gun is as they would say "not worthy of them".