On my 71 looking from the front the rubber bumper stud is at the back edge of bucket panel. But your inboard bucket is the one that has the gap. That brace on yours looks a little wonky. Try straightening it out.
They were used to tie down the rear of the car when being transported by the car haulers. They are bolted to the rear frame rails near the mufflers. Some dealers removed them and some did not. I have a picture somewhere if I can find it.