Omega Speedmaster 145.012-67 a possible Ultraman? on an auction!

This is one of life’s great truths, and certainly not specific to things horological.

I cannot remember where I saw it — I think it was here but am too lazy to launch a search — but I recall reading that the “SP” designation indicated that the case had a higher water resistance. That made some sense to me, given that it appears on cases without pushers. Of course, it may mean different things on different cases. In any case (no pun intended), it certainly appears on non-Ultraman Speedmasters as well as other references.