i am confused. i have two sets of seat belts that i thought were removed from two different 72 el caminos. one set has a shoulder belt that comes down from behind and above the seat on the driver and passenger side and has a flanged pin that interlocks with the lap belt. the other set has belts with similar mounts but there is a buckle instead of a flanged pin and it doesnt look like they provide a three point hold. also the set with the shoulder harness with pins have smaller buckles and i think are just marked GM the other set has larger buckles and are marked J Robbins or something like that. were there two different styles in 72 or do i have a year difference thing going on here?