Seat hinge cover for 73 Swinger.....

Yeah, strange. At least you know to not look for '73 style. I picked up a '75 bench recently that someone had covered with '73 style covers, but it has the '70-'72 style hinges and hinge covers just like on my '72. But the hinge releases are '75 style. The whole thing is really weird, it's a frankenstein seat, I didn't even know it was possible.