38-39
That's a grab handle.
The photo is a publicity shot for Ford. If you look carefully, notice the pole near the ground behind the truck which is holding the bottom edge of a large piece of white fabric. This was done to hid most of the background images and having a mostly white background made touch-up so much easier in the days before we all could do it electronically. I haven't looked but I bet this scene is replicated in some Ford booklet or showroom album.