Those seats were used in 1971-1981 Camaro and Firebired, Monza, and Sunbird. The upholstery job is what is disguising them. Most had vertical pleats with 4 buttons on the seatback. Could be custom covers or a non-Camaro version, like the Firebird or Sunbird. Judging from the velour looking inserts I would say an upholstery shop did their best to disguise them as mopar seats using a moparish pattern. These seats were originally used on the 1970 Vega and were than slightly modified for install in the F-bodies and related gm cars that got them. There were two styles of seat backs depending on whether the car came with standard or deluxe interior. It is hard to tell in pic whether yours are the squared off version(deluxe) or the more rounded standard style. Both used the same seat frames. You can also fix the caved in part on your driverside seat bolster by firmly grabbing the bolster and pushing out away from the cave in. There is a big piece of wire in there that holds the foams shape. It got bent from somebody slaming into the seat.
I just re-upholstered a pair for my 1978 Camaro, it's a for sure those are as described above.