No idea what it is called goes in the trunk thingy!

Finishing panel sounds good to me, makes sense on the fold down seats to hide the back space of the trunk.. My SE has one when I got it from the original owner. It also had what was left of what I believe was blask carpet, the only reusable piese I have left of it is the wrap for the gas tank filler tube. A deluxe trunk option? No idea.