There are two sets of "clasps" for the back seat. There's the one with two clasps, and the other with one clasp and the seat belt for the middle seat.
I assume that installation/removal varies depending on the model year, but for the second gens, you definitely do NOT have to replace the whole seat. If you fold the back seats down, you can lift up the flap behind them (where the jack handle is stored on mine) and access the bolts holding them on. Easy to replace, just make sure you get a replacement that's fully functional.