EARLY 260 SHOULDER STRAP CLIP

Can any body tell me how the shoulder strap clip (cheasy little plastic clip) mounts to the interior?  Is it just a screw into the plastic side window frame panel or is there a threaded hole in the side widow frame?  I have poked around in the hole in the plastic side window frame but haven't been able to locate a hole in the window frame itself.  I find it hard to believe that it would just screw into the plastic.  I need to find a solution to the belt cutting into my wife's neck!  Happy wife = more money to spend on the Z :)

Edited June 10, 20195 yr by GGRIII
mis-typed