They're solid rubber of the color ALL the way through. The paint I put on can bend some with it, but not too much or it'll crack. I've painted the one on their now, it's fine. Sand it, primer it, paint and clear. Looks fine.
They are solid, the color which matches the car and molded in such a way when they come out, they're shiny, like fresh paint, but it's just shiny rubber.
They have metal as the base, which you have to be VERY careful when removing, or it'll bend (as I found out)
I found a new OEM one for a cougar, a black one on eBay. Last left side one they had...perhaps the last in the country New Old Stock. It's painted and curing before I put it on this week.
The trick to keeping them nice... don't park next to someone