Some answers...
Hey Bro,
I asked D here at work since he used to work for the company that made the stuff and figured I'd post some answers.
The material is called Rubatex and it's a type of closed-cell rubber. Unfortunately there's no way of fixing the pitting. The rubber has been compressed in that area and doesn't return to it's original shape. Furthermore, years of UV rays has affected the material. His suggestion is to get it recovered by an auto/marine upholstery pro using a UV stable vinyl. The other possibility is to fill in the pits and attempt to repaint. Not too sure how that'll turn out.
Anyways, final option is to buy a new one.
Cheers!
--T8