I seem to remember reading somewhere that from the factory chassis's were being painted O/Drab, the chassis on one of my 109's was Olive Drab, not just the outside bits you see, it was all over as you can see in this image
the chassis was on a jig at the time and had been pressure washed, to reveal the Olive Drab paint, cheers Dennis
ps my personal preference for chassis n diff's etc is Gloss Black,,. like this
this is 113-372.
Here are 2 images of my 109 Wksp rebuild job, with my old mate Graham D inspecting the work LOL
here is the same chassis partially painted in Gloss Black
refitted with Salisbury differential
hope they are of some help, cheers,,.