Seat covers

I second RedFish's recommendation on Legendary. Worth the $s.
Checking the Legendary catalog, the vinyl grain used on the seat skirts is different from 73 to 74. The same grain was used on the inserts. If the seating surfaces on the seats is the same, I'd assume you're dealing with original upholstery. If they are different, I might even suspect that a brand X bucket may have been installed.