Depends on the rear doors. If your Sub. has barn doors, it used the same rear bumper as a '40 panel. This bumper would have a dip in the center so you could get right up to the back of the truck with the doors open. If the Sub. has the liftgate/tailgate, then it used the regular bumper (no dip) that was used on the back of a pickup. With the tailgate down, it didn't matter how far the rear bumper stuck out as the tailgate stuck out farther. Both of these would be 1940 bumpers with the 2 narrow grooves in the face of them. The '39 and '41 rear bumpers are different.

To be long remembered as he's cruising in
The Passing Lane