Careful Reading - 63mm El Nikkor lenses

I recently got a 63mm f.2.8 EL Nikkor. To get magnification higher than 1:1, I got a 40.5 to 52 step-up ring and planned to use it with a BR ring. That's when I saw the original Nikon reversing ring. I got that too. I arrived today. The seller described it correctly. It's for the 63/3.5 or 50/2.8. It's not for the 63/2.8. I must have several 50/2.8 EL Nikkors here somewhere but the enlargers with lenses on them have CE Rokkor-Xs on them.

Thread title tweaked - to make it a bit more revelatory!
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