I have recovered the seats in my '03 2500. They are easier to work on than old seats, they don't use hog rings just plastic clips that are built into the covers.

Ebay is the best place to find stock seat cover sets that were taken off trucks when they were new, for katzkin leather conversions, but you've usually got to buy the covers for all the seats, not just one.......

For the seat foam, I just ordered new mopar foam from the dodge dealer.