How did the factory paint our trucks?

[LongBox]

I'm still working on cleaning up my 69, and I've been machine polishing the various panels. I notice that the paint on the cowl panel is much thinner than the paint on the fenders, hood and doors. Were these trucks painted before assembly? Why would the cowl panel have thinner paint than the other panels? And, should the underside of the engine hood be painted body colour, or black?

The other question I have is what type of paint was used on the inner fenders and rad support? Was it glossy black, semi gloss, or flat black?

Any insight into this would be appreciated.