In my 91 with 60/40 bench I bolted up buckets from like a 97 i think? Both trucks are extended cab and the passenger side seat from 97 was loooonnnger in the bracket then the bolt pattern from my 91 bench. The one i bought had that "easy-out" feature where it slides way up.(I think the rear inner bolt on the floor is there on the passenger side, you just have to locate it since it wasn't used for the bench)
To make along story short, I could bolt up the back holes in the pass seat perfectly, then I drilled holes thru the floor for the front bolt holes, big bolt, fender washers underneath and the plastic surround and it looks 100% stock. The driver's side fit with no modification. Now I have headrest, armrest, and room for a shifter!
1991 Silverado ECLB
LM7-T56