they were most lily left in the body shop. that on is a wide molding here are a few pictures of the clips not a good one of the back door but you get the pictures. they are a off set plastic. with a lock pin some were in this album or the #2 on this 75 is more pictures.
https://www.dropshots.com/jer57747/albums/149937
as I recall the ends were steel of some sort. then did a lot of stacked washers and steel tabs on the quarter joint. a subject to rust. then the plastic one you needed to push the pin in to get it to release. there are some still around if you get lucky but they are no longer produced. if you have the offset plastic you can use a wood down to lock them in with. as I recall there was a steel snap over clip in between the corner and the end. it was rusted out on one side so I cut the other in two to make two of them.