Trying to determine original paint color for a 1930 Model 68.

Can anyone tell me what they discovered when stripping/repainting their Buick from the circa 1930 period in terms of the painting process? Did you happen to notice any primer laid down as the first coat from the factory? The reason that I ask is that mine never seems to have had any primer. I believe that my car was repainted once before possibly in the 1960's. The black areas (fenders, aprons, etc) of mine were sprayed as follows from the top surface down to metal:

Black

Gray primer

Red Oxide primer

Black

The final black at the bottom I believe to be original but there is no primer under it.

On the upper portions of the body I have:

Black

Gray primer

Red Oxide primer

Maroon

So I think the original body color was maroon which would be reasonable as it was one of 3 colors available on the car (maroon, green, or black). The thing that confounds me is the fact that there is no primer beneath the maroon and also that the firewall is painted as follows:

Black (not followed by gray primer as on other areas of the car)

Red Oxide primer

Maroon

So there are basically two parts to my question:

1) Did they use primer at the factory?

and

2) It was my understanding that the firewalls of these cars were always painted black. Is this true or were there any examples to the contrary where they were painted body color?

Thanks,

Interesting. I too thought all firewalls in the era were black. Mine was originally, as best we could tell, and I have seen a HPOF also of black.

John