Over the years I have had many many NOS Model "A" parts that had various shades of engine green. I heard a story that at the Rouge where engines were made, left over paints of various colors were dumped into the green paint vats used to coat the engine, engine covers, flywheel housing, transmission & water pump.
Bob, pretty sure that was a Wives' Tail (-or Tale) as there is a M-Spec (M-200) for the original paint that was specific to the formulation, ...and secondly it was enamel and the Ford paint colors back then were Pyroxilyn.