I 1500 grit sanded the gray areas with a little flat sanding block paying close attention not to hit the black part of the cover with the sandpaper. Washed the 2 pieces off really well with Dawn dishsoap afterwards and dried the pieces thoroughly. Painter taped the black areas, leaving the gray areas exposed of course. This was time consuming because there is a little valley between the gray and black areas that was a pain to tape off correctly. Making the radius on the corners was tricky too.
Then the REAL competency of my artistic ability showed up...........I ghetto painted the gray areas with red KRYLON
paint and slopped about 50 coats of clear over that to finish the job!
I and the wife were impressed with how it came out. LOL
BTW, you can clean the black surface where any overspray may seep through with some NON-ACETONE cleaner and make small work of cleaning the overspray off wherever you need to.