R12 is the bad gas R134A is not as bad. being an 80's car it could be either look for a blue sticker somewhere in the engine bay that has aircon details on it and 134a in the background.
ther will be 2 fittings with schroder valves in them (like a tyre valve) i would let them "down" like you would a tyre, just use a screw driver or something. you should only have high pressure on one side, but do both to be sure.
like you said ditch the belt and unbolt the compressor, lose the condensor off the front, lost the 2 hose/pipes tha go to the firewall.
in the car remove the glovebox and you'll see a big black box that the two firewall fittings go in to, if you know what i mean. take it out and remove the evaporator (looks like a mini intercooler!!) now you can put the empty box back in or you can source from the wreckers the tube that joins the 2 and does away with the big box. from memory i think someone has said you can use non aircondtioned AE71 and KE70 tubes plus some other early toyota models.
