Are they from out of a Mopar getitgone or are you clueless what Make and Model its from and do you only have the one or both? Either way, an exceptional find. I can vaguely recall the only conv I've seen with shoulder belts was only for driver & their front passenger and the front bucket seats had a bracket at top on side for the belt to slide through like in most modern conv's with shoulder belts. Is there a provision for that?
Somebody definitely has to get in on this and enlighten us and with more pics too!