A friend has asked me to detail his car. It's an older Mercedes, I'm guessing mid 80's - 90, that belonged to his father, before he passed away. Sort of a gold color, and really good shape; about 50K, and always garaged. He doesn't recall the car ever being waxed or polished! The one area I need help on is the outside mirrors. They both seem to have the black paint on the forward side of the mirror housing worn, starting to reveal a yellowish colored material....maybe fiberglass??? I'll have to do something with them, and it seems they'll have to be repainted. Anyone know if this should be flat or semi-gloss black?