There might be a thread on this (about two+ year old thread). What I remember from that is driver side seats should be compatible, but for passenger side, there was a change in the plug for the seat controls after the 92 model year. Essentially, 91-92 passenger seats might not plug into 93+ cars and 93+ passenger seats might not plug into 91-92 cars.
Again, this is from memory (from a discussion I had w/ an NSXer who did a seat swap).