Where are the bolts??

Trying to remove the panel under(behind) the rear bumper. The top bolt goes in from the inside(i can see the back side from the outside). How do you get to the head of the bolt? It appears to be in the opening between the trunk floor and outer quarter panel. The body and chassis service manuals do not address it.

On 67 dart the panel behind the bumper is not removable, are you sure it is removable?