I ask as I think I will need to replace both of mine.
I looked in on mine today, and the outer skins are quite rotten, as is the inner support.
I do not know if they are all in one when you buy the part from LMC, see the link below, part no7.
http://www.lmctruck.com/icatalog/cbe/full.aspx?Page=18
There is no pic or illustration of how the inside looks like.
It also looks like there are two parts t make up the repair, the outer panel and the inner support ??
If you have a photo or photos of the inside and outside of what is needed to repair or replace this, please post up.
If you look at the truck below, it does not look too bad, but see the brown mark at the bottom of the rear end of the fender. The support behind it is rotten too.