The rear interior panel below the quarter window has two molded tubes that appear to be for screws but there is no corresponding penetrations for screws on the steel panel. Are there supposed to be screws in the bottom of the panel or are they preformed and just not used?
All the photos I see of these panels for sale have holes through the outer vinyl.
This is for a 1969 XR7.
I just installed my 70’ panels, and yes, they accept screws. Front side of panel, should have corresponding holes in the vinyl. Place your panel to the structure, use 1 or 2 panel clips along the jamb, to orient the panel and with a pointed awl/pick, locate the screw holes on the structure. Can be a bit tedious. Note that the plastic, can be brittle.
Thanks for the reply. Still not seeing where the screws go into the car body and both panels had the screw holes covered with foam on the inside I presume to stop rattle/squeaks.
It seems like the seat bottom would squeeze the lower part of the panel into place firmly. i must be missing something. 
My car didn’t have the holes either. Very possible the worker at the plant decided they weren’t necessary
Does the seat bottom hold your panels in firmly?
I figured people were putting the screws in when the clips failed or fell off.
Both screws thread into holes into the far rear of the side panels. If the screws were installed by the factory, you should have holes in the vinyl showing where they were. If not, the factory may not have installed them. Or maybe you covered up the holes in the side panel with that grey goop.
The seat does hold the panel quite well at the bottom. Good point about the gray goop hiding the holes. However, the first holes were added by me during the most recent rebuild using the awl method described above
I am inclined to install it without the screws but does any one have a photo of the body panel with the screw locations?