They look pure GM to me... 99% sure.
100% sure they aren't Ford.
I am thinking F-body as well, however, GMs are like Fords in that the same seat frame and buns can be used over a wide variety of models with only changes being in the covers. They could be A-body of a similar year.
IMO 1970-1980 would be the year range for F-body.
Narrower range for other models... 72-77
Edit:
I took a longer look at those...
I am no longer certain they are not Ford seats!
I am thinking back 25 years to our 73 Torino and thinking it had those seats... Been a long time ago, but they look familiar. Less and less like GM seats every time I look at them.
It would help a little to have better pics.