There was a fella on the H.A.M.B. rebuilt his A.D. bench seat entirely with foam,he even gave the foam density best suited.
AFAIK the different colours denote the different densities.
The lower (base) was much denser than the backrest,he then used a re-pop upholstery kit from one of the many vendors.
He also made the backrest slightly thinner which gained him some much needed extra legroom.
In the end it looked factory,he did a fairly in depth "How to" documenting the build i'll see if I can find a link.
Here's his build thread,I realise it's a different truck to yours but there's some inspiring stuff!
Indeed a talented man!
http://www.jalopyjournal.com/forum/threads/my-53-chevy-truck-project.629357/
