35 Trucker, I don't know how to tell the difference between single or double action. I did notice that the '41 also has shocks on the front, as well as the rear. There is something else a little peculiar about this truck, the grill is notched on both sides to allow for the front bumper to be mounted extra high. The notches look like they were done at the factory. Neither one of my other 1 1/2 tons (both '42s) have the shocks or notched grill.
John
