Checked the alignment of the factory drilled holes on the S-21 seat back frame. One frame was good the other misaligned. Bolted the bad one together just to see what would happen. It was a mess.
Checked it out on the drill press. If one where to assume the first bend from the base was inline with the base, clamp it down, then drill, you would end up with exactly what the pictures show. The rod depicts what the pins would look like in the seat track. I know. I tried it. Doesn’t work.