Odd. Several years ago, I posted a thread comparing my disassembled gen 6239 pushers (removed from a sealed Rolex package) to Ofrei's (PD61.701) &, after sizing for my case, I could not tell the difference between them. You do know that the pusher stems must be cut & slotted (for a screwdriver blade) to fit your case?
If you have the original pusher, simply measure & cut the Ofrei to match it. If you do not have the original, install the pusher into the case & test fit the movement. Cut its length so that the movement clears during casing, but has sufficient length to operate the chrono when assembled.