Smiths were the only watches worn on the summit of Everest in '53. The proof.

[Dr.f]

I suppose it’s possible that Zenith and Rolex used the same dial manufacturer (Singer?)

Remember at this point Rolex made literally nothing in-house. Unlike a certain other brand whose name escapes me at the moment. Cheltenham. Damn it’s on the tip of my tongue. Nope, I can’t remember. It’ll come to me.

Is there a reference for that Zenith Pilot
John