1/4 panel skins

The body man I was talking to had just done a 1/4 replacement on a 67 Barracuda using those stamped Taiwanese panels ,cutting out the old ones of course but he mentioned that they are skins, not true 1/4`s and designed to go over another panel. I have never worked with one myself. Doesn`t the term "skin" imply that they are not meant for replacement panels? Anyway you slice it ,I`m going to have to use one, as they are the only thing available. I`m just going to cut pieces from one to use around the rear wheel.