albertaboy...Pick-ups back in the day were not nearly as accepted for "personal" transportation like they are today......hence, Ford differentiated them by categorizing their usual livery as "commercial", rather than "passenger car". There were enough differences to warrant doing so.
Below is a drawing (on the bottom) of the differences between 1940 passenger, and pick-up fenders.
Look at the pale yellow-enhanced, formed spear that is stamped into the side of the hood on this '40 pick-up. It continues rearward to meet-up with the wider, stamped horizontal spear which is stamped into the pick-up door. The '40 passenger doors and hoods DO NOT have this feature stamped into them. Also note the difference in the shape between the two hoods (passenger and commercial) at the rear where it fits the cowl on the side between door and hood.......totally different hoods. Hope this helps ya. DD
One more pick-up pic to help you see the horizontal, STAMPED feature in door and hood, not found on passenger cars, below.