The set I picked up used, are several years old. Their guides were fine and the seats are still in them.
Some early SBC an SBF ones I saw had soft guides, they were also oddball sizes on the od. Had to order them from PEP. Had to be careful when removing them with the air driver or the would mushroom. All the small block Mopar ones I have seen have had .545 od guides which are an easy to get size, haven't seen any soft ones in them.