Seat bracket identification

[Nele15]

So I bought a 72 Blazer last year, had new seat frames made by Rick's and tried to fit the passenger rear brackets on but the holes don't line up and it's a little tight in for the rear bracket, the handle also hits the back of the seat. Looking at the front bracket, it looks like a 73-77.

Looking at other posts it looks like the rear is a correct 67-72 but someone was using the front bracket from a layer model. Is it possible that both of these are later than 72?

Thanks for looking.