97 3rd-row seats should fit in earlier Gen-II's as long as the seat latch bars are in the floor and the fender well tops have the mounting brackets (you'd have to pull the plastic fender well covers to check).

Fitting the Gen-II seats to a Gen-I could be done, but, not without a lot of work.

The Gen-I tie-down loops in the floor are not the same as the Gen-II seat latch bars, nor are the wheel well shapes the same for mounting the seats. The Gen-II seat latch bars are towards the center of the floor and recessed in small wells below the floor. The Gen-II wheel wells are taller and the mounts for the seats are welded fittings on top of the wheel wells. If you were going to salvage some Gen-II 3rd-row seats to mount in a Gen-I, you would probably want to cut out the fender well mounts with a torch to try and re-use, or, use as templates for fabbing some new mounts.

If you'd want to have the seats fold up as in the Gen-II's, you'd have to fabricate seat latch bars and mounting brackets for the wheel wells. Could be done, but, not a trivial bolt-them-in project <img src="/forums/images/graemlins/kewl.gif" alt="" />. It might be easier to fabricate a frame to mount the seats more permanently in the down position. But then access to the seats would be more difficult (the Gen-II split 2nd row seats slide forward for access to the 3rd row) and you'd have a more permant loss of rear storage space. Take a look at MontyMcV's project: MontyMcV 3-rd row seats

Here's a shot of the back of a '90 Gen-I:


Here's a '97 Gen-II. The latch bars are recessed in small wells in the floor.