Dog,
Look close I and I think that you will see that "Digger" is the "Motion T-bucket Man" The photo on the model box does not match 100% to the original Weird-Ohs prints. But the originals print does match the Motion decal. Hand on shifter, Header coming out of helmet, wheels in air at same angle, and piston flying out of engine! I am in process of making contact with the original artist of "Digger" to see if he recalls doing work for Motion. Hmmm....I wonder if J.R. gets paid royalties off of the model car sales being that all of the logos and artwork are copy writed etc.
Anyway I think that you solved the mystery enough for me to end the debate with my body man.
Dog You are the Man!!