Upholstery on Back Seat top, 67 Barracuda

I was going to re-upholster my seats for a 67 Barracuda today. They are the fold down type. I unhooked the old upholstery from the back top section, but it seems that there are hog-rings holding the interior (inserts) portion of the upholstery to the seat frame/springs.

It would seem I have to remove the back metal panel to access these, but that back panel (where the carpet would be) is not only held by a few screws, but is also spot welded all the way around. In addition, The upholstery that I got from Legendary does not have a sleeve on the listing to insert metal rods at those points that would (theoretically) be hog ringed to the seat frame.

Is there something that I am missing? I'm sure somebody here has replaced the upholstery on these seats.

Also, just to check and make sure I will do this correctly. When doing the front bucket seats, do you just cut through the seat foam to hook the hog rings for the middle insert section?