The striker is the u-shaped piece that bolts to the side. The latch on the seat clamps to this to keep the seat in place. Bosses are the threaded holes needed to screw the latch to the side. It will be under the trim. There are spacers as I recall behind the plastic. Don't know which seats will swap in. Certainly 85. Don't know about newer.

One other issue. On mine the carpet runs up the back of the rear seat. On the split seats I've seen the carpet runs through the crack under the back, staying on the floor. The seat back had it's own carpet that was not attached to the floor.