Unless the paints had no care at all, it won't have faded noticabley against fresh paint, and even so, some good cutting compound would bring it back up. Fading it down the wings is less to do with the fade from the elemnts, and more to do with the variation in the paints.
Paint code should either be on the plate up into the scuttle, or on the B post. Saying thou I've never looked on a VW. Could be anywhere, crazy Germans