The back of the one pictured above and the others have Pontonier and 600-1.
I made a stupid mistake, I only have two white banded buckles, the other two are like one in pic below.
The one in pic below states 300-1 patent no. 3393433
The others state p-535.
One member said his rear buckles were missing, but identical & like in my case, only the front white banded buckles were installed.
I bought the car in 1994 when nobody cared about or hardly knew about these cars, I see no reason as the other member here why they were tampered with, and even found a factory safety hazard warning label that stated 'seat belts loose' still attached to seat belt bolt once rear seat was removed.
I don't mind taking time away tonight to help resolve issue for my education on E Body & any future reference.