Nelson provided me these part numbers:
2 Each: MS28775-117
SFK or CR 711805
Looking in the “(not) Illustrated Parts Manual” I have the below o-rings and seals listed for the standard AN/MS numbers for that valve:
1 – AN6227B-10 – O-Ring
2 – MS28775-117 – O-Ring
1 – AN6226-45 – Seal (this I believe is same as the SFK/CR 711805 above)
If needed, flap valve also list same parts w/o AN6227B-10. With that the AN6227B-10 may be part of the pressure regulator and not part of the selector shaft sealing and may not be needed to fix your leak but having on hand never hurts to have on hand as it’s part of the retract cylinders.