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I have seen a Lot of RPS seat backs and never seen off center holes. I wonder if someone else replaced the top piece on that RPS, which you could also do again.

Left as is, this is the reason to use the Lee recessed vertical rod holders. They have a large enough top flange to cover the off center situation. Simply grind out the holes as needed so the Lee holder will center, and screw them in at the center location.