My RV-4 is black on top and on the leading edges. The fiberglass doesn't seem to care.
HOWEVER, it is shocking to see the leading edge ALUMINUM parts distort after a descent from cold altitude to a hot sunny ramp. I just about soiled myself the first time it happened. But as soon as the spar warmed up and grew to the same dims as the skins... gone.
F1 Rocket and F4 Raider components
RV and Rocket Accessories, Tailwheels, Tools, & More
F4 Raider - under construction
F1-H Rocket "Crazy Horse" - sold
RV-4 "Chief Pontiac" - sold