1/4 panel skins

If he is calling a "true" quarter panel a panel that includes the sail panel (C pillar) I would call that a complete quarter panel. I would call a quarter panel that he calls "skins" a partial quarter panel because it doesn't have the sail panel (C pillar). A factory replacement panel for a door is called a "door skin" but it doesn't get put on over the original panel it replaces the original panel. Even it a panel was supposed to go over the original I wouldn't because of the problems stated earlier. The factory sheet metal could be called it's skin because it covers the car and if you take it off you will be able to see the guts.

Chuck