Steve, More than likely some parts are missing. The rear seat top latches onto a bar, theres a release mechanism that lets it fold down. Your going to need some additional parts to make that seat work. You can buy them on line...so no worries there.
I dont know if a Birds rear fold down seat is the same as a Camaro's though.
Post some pics using photobucket. It might help other's here to I.D.ing it.