While the seat no longer has threaded holes (the nut plates were removed). There are nut plates on the back rest, 177642A1. In order to install, use a utility knife to cut the seat cover at the top of the seat to allow the back rest plate to slip into the seat. Align the threaded holes in the back rest plate with the holes in the seat back and install the hardware. This has been done this way for a while now in production. There are no other changes planned. 4-1-99 cw.