I accidentally bought (because of choosing the wrong front/rear seat cushion set) the replacement vinyl covers meant for a 68 fold down rear seat some years ago (#CR468M108F at YearOne) and had to learn the hard way that they are missing about 4 inches to fully cover the back seat of a hardtop coupe... Thus my professional upholsterer had to modify them a little bit; that´s the reason why my back seats look a bit different from the stock look...
So I can say for sure that at least the vinyl covers of rear fold down and non-fold down seats in hardtop coupes are different. Being not experienced with convertibles I don´t have any clue if it´s analog for their rear seats...
