I have a 72 Cuda. The seatbacks are plastic panels as shown in your top picture.Well without pics its pretty hard to offer any suggestions. As far as figuring it out on your own, Google is your friend, just look at the various years. 72-74 are pretty different from 70/71. Easiest way is that 70/71 have plastic back panels and 72-74 dont. Top set is 70/71 bottom is 72-74
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Then you have 70 or 71 seats. The difference between them is the seat back release button.I have a 72 Cuda. The seatbacks are plastic panels as shown in your top picture.