All JDM CRX (and UKDM also i think) had backseat. Fabrik or leather. I bought myself one in june and it's BOLT-ON (if you get all the brakets with it) If you want the belt, you'll need the complete quarter panels in the back. i bought mine here in canada for about 350$ (cnd $) for the kit... it takes about 15 minutes to install and looks really nice.

Actually, i never intended to take passengers in the back (very little leg and head room...) and illegal (i think..) because, here, CRX are consider 2 seats car, so...

Here's a picture of how mine looks