They look like recovered 72 E-bodies to me.
70 & early 71 had different style backs and latch buttons, the button assembly and back were two pieces in those years. 73 & 74 had vinyl fabric backs and levers to release the seat latch. Those look like the late 71 and 72 E body and 71 through 74 B body that had 1 piece plastic backs.
The portion you sit on of the backs and bottoms in 70 & 71 are very flat while the 72, 73 & 74 (e bodies only) had foam bolsters on the sides and it made the seats more contoured and less flat.
72 was a transition from the older style to the newer style and it appears to be a 71 style back and the 73&74 later style seats but I have never seen any B or E body with pleats in the headrests.