I used the restore black on my old van and my newer one. has worked for me, just clean the real good and give them a couple coats and it will last for a while.

I've had success with Armor All. But I'd go with spray paint.

I've never seen them in Gray but that doesn't mean it isn't. I know they do start to look Gray after they have weathered for a few years.

As I said, mine were grayish and I put restore black on them and this is about 8 months later.
https://cimg3.ibsrv.net/gimg/chevrol...0deb6055c4.jpg

Looks good. Mine are gray OEM, I can see that because in the interior, where no sun or water never gets to, they are grey. Do you mind sharing a picture or amazon link of the product you are using?
Thanks.

I don't even remember where I got it but I do know it is called restore black. I will try to remember when I get home to take a picture of the stuff I used.

My interior is Gray also but the exterior was never Gray. That may not be your case but my last express was the same, Gray interior and black exterior.