I've been doing my seats myself for the '68 with Legendary covers, foam from them (it's really ACI brand), using an installation kit from
www.seat-guy.com. Ben is an Olds guy (though he just sold his '66) and is great to work with.
Ames Performance makes the correct molded seat chrome for the edge of the seat plastic too. I got an order of some new screws, seat chrome trim, seat bumpers, and it added up to $240. Stuff came in and is nice, but it's always the tiny stuff that kills your budget.
The good part is that '69-72 seat backs are all the same, not terribly hard to find (and interchangeable side to side)... you can restore with SEM landau black.