Attaching the tonneau cover to the rear seat upper

Still wading through my 67 Barracuda vert’s rear seat issues. I was told if I found (hasn’t happened yet) a rear seat, I needed to make certain I got the “back seat upper trim” piece that the tonneau cover attaches to.

My car did not have any trim piece attached to the seat back. Anyone have any photos of that piece and how the cover connects?