Here's what I posted to someone who was dealing ewith seat-belt issues,
the seat backs remove similarly - there's a "metal wire bracket" in the center of the seat back that must be squeezed together to release it.
"I don't believe you'll have to remove much. Taking out the seat cushion will give easier access to the retractor. The cushion is retained by a wire clip just beneath the leading edge of the cushion. The wire clip is shaped like this |_____| with the arms attached to the seat frame. The cushion has tongue-like extension shaped ______|
When you pull the clip slightly up and forward the seat is released. It just jams in at the rear part. If you're agile you can just get your head down there and see what I mean. I never re-fastened mine so I can easily life the cushions out and store things there away from other eyes.
Even if you need to remove the seat frame it's not too bad, 4 screws and just unplug the power connector. An easy one beer job. GM may have used some wacko-sized screw heads on the seat belt stuff to keep us from messing with it. A Factory Service Manual shows details and torque needs. I always suggest a FSM and both Haynes and Chilton manuals too. Between them all most jobs are a piece of cake, from 1 to 6 beers."
It sounds much harder than it is. If you gently, but firmly pull the seat back away from the "bucket" it's in you can see the attachment means.