1965 Valiant bench seat seatback issues

That is how they look, the center pins. You must have a stop broken or something. The passenger side should be an opposite duplicate. So what's missing on the driver's side? I have seen, when I worked at a dealership, heavy (fat), people destroy the framework of a seat. Compare the sides to each other and see what's missing. Cut the hog rings and pull the seat covers off. You can get a hog ring pliers and rings at any farm store, cheaply. The springs in the center may also be broken, then it's good luck finding a replacement.