Underside of cab paint

[fireguyfire]

I’ve been working on the underside of my cab making a few rust repairs preparing it for a full new factory paint job.
It’s on a rolling wooden dolly I made so I can move it around my shop, so the underside is easy to see, and upon looking at it closely it appears the underside was never painted; it’s just a greyish colour with a light surface rust in areas.
We’re the underside of these cabs painted body colour by the factory?

[PwrWgnDrvr]

At least some were. And special order undercoating was also available.

[soopernaut]

http://sweptline.org/forums/viewtopic.p ... nt#p180674