From the excellent CRG report by John Hinckley:
http://www.camaros.org/assemblyprocess.shtml Chevrolet Assembly - Paint Shop Operations Details
The primary function of the Paint Shop on the Chevrolet side of the plant was to paint the front end sheet metal, but there were several other unique paint systems as well that processed many other parts.
Raw Metal: The front fender outer skin and the long inner fender reinforcement were received separately from the stamping plant in order to get more pieces in a standard rack; these two parts were spot-welded together in special fixtures which established the "crown" of the fender so it matched the contour of the hood, and the raw welded assembly was then sent to the primer "Flow-Coat" line.
Sheet Metal Painting: All raw parts (wheels, brackets, etc.) and the front end sheet metal (hoods, fenders, lower fender extensions, header panels, front valances, radiator supports, inner fenders, etc.) went through a cleaning, degreasing, and hot phosphate system, then through a flow-coat booth where it was deluged with black primer from all directions and then baked. The sheet metal parts that got exterior color were pulled off the prime conveyor and loaded on another conveyor buck, in car position, for finish painting; it got a coat of primer-surfacer that was baked and lightly wet-sanded, then got three coats of lacquer, a short bake to "skin" it over, a light wet-sanding and wipe-down, then it went through the final re-flow oven at 275F for 30 minutes. Next was an in-line repair booth where Z-10/Z-11/Z-28 and D-90/DX1 stripe masking, spraying, and de-masking was done (including lower fender blackout when required), followed by another oven. After cooling, the conveyor delivered the buck carrying the color-coated parts, in the same sequence as the cars on the main assembly line, to the sheet metal subassembly area. Exterior color lacquer was supplied by DuPont, and both Fisher Body and Chevrolet Paint Shops at the same assembly location were supplied from the same DuPont-mixed lot in order to minimize any color-match problems. This wasn't an issue at Van Nuys, as their recently-consolidated Paint Shop had each car's front sheet metal on a buck just ahead of the body shell so the entire exterior of the car was painted at the same time with the same paint; that set of sheet metal eventually met up with that same body again after Body Drop on the Final Line.