From my Melbourne build ute (3/75 HJ): Firewall/plenum internal area painted black first, the front clip was painted off vehicle (clean cad plated attach bolts except for the two lower rear guard attach bolts), the front doors were painted in-situ (bolts painted and bare metal/no paint between hinge and body).

I do have a couple of pics of original maskings I took as I disassembled mine I can email/PM.