Gosh I'm trying hard to help. These pics were found on Bing by clicking the Images tab...but they're from Cookieboystoys site. It was slim pickin's and I'm still looking. On Buttercup the seat insert seams were extended down through the padding to attach to the frame of the seats, keep in mind that substantial padding work may be needed to change the 'pattern' (I used to work at an upholstery shop) and the 'horseshoe' style seam is difficult to reproduce and we used to charge more for that. In the sedans the rear seat upholstery is stapled to a Masonite style board (just like the door panels) on the back and a fairly simple foam block and wire frame on the bottom. I've never taken apart a wagon/runabout rear seat back. I'm only assuming by your handle that your car is a 78, that's what year mine was. The blue pic I posted before was my back seat in Buttercup (thanks again Scott for leaving my gallery up!
) Hopefully somebody else will join in with pics too.
Hope it helps at least a little.
If you recognize an image as yours and want it removed, send me a pm and it will be gone within 24 hrs. Don't mean to harm or offend anyone.