Will the rear hatch from a 1983 camaro fit a 1982 firebird ?

 

All rear hatches from Chevy and Pontiac from 82-92 are interchangeable, the only difference would be if the hatch has a spoiler because the mounting holes would be different. Oh and of course if it has defrost or not, it's basically a hatch lid and a big piece of glass.

 

other differences are the third brake light. deck lid mounted brake lights have a contact patch on the bottom of the decklid and on the rear plastic panel.

you will have no problems with your swap, barring the defrost.

 

hatch glass outside mounted brake lights have this also. Mine does at least. So if this contact isn't in touch with the other contact the third brake light won't work?

 

Ya, 86 is the oddball with the exterior glass mounted brake light.
If the contact isn't working then you won't have the third brake light.
91-92 with the interior mounted glass brake light had a wire going to the inside roof under the headliner.