any way to tell if your barrel is chrome lined?

Most of the time, one can tell by looking... but of course that requires a little experience and knowing what you are looking for.

I know a friend that owns a small shop and uses chemical "cold blue" compound as a test on used guns he takes in trade -- I can not tell you if it in fact works, but it seems logical? He wipes a little with a q-tip around the outside of the chamber (clean), in theory, if the bluing takes, it is bare carbon steel, no chrome plating.

I can run out to the shop later and give it a try, if no one else has any input on the method?

Someone posted a pic a few days ago. You can actually see a lighter colored chrome ring when looking at the muzzle and looking at the extension. It was very obvious in the pics.