Basically,the bare metal unibody complete with fenders and door,hood and trunklid was dipped in a metal prep acid solution,then rinsed in clear water and dried,then dipped about 1/2 way up in a vat of latex primer[dark grey or black in some cases].This was then washed off the exterior panels.Then a coat of red oxide epoxy primer was sprayed on all the exterior surfaces,followed by a coat of green-grey epoxy that was sprayed over the red oxide and most of the easily viewed inners too.This was then baked,and the exterior was sanded to remove flaws.Then 2 coats of acrylic enamel were sprayed on,and also baked.That is about it.Few parts were painted off the cars by 1970.