MM:

I believe that John was showing us his collection, which includes all the versions of the Carrera 12 Dato.

He is not showing the Reference 2543 / 2558 models from the 1940s, three of which are shown below.

By the way, the chronograph that you show is not a Reference 2923. The one that you show is a Reference 2547, as shown in the 1946 catalog (also shown below). This Reference 2547 is the same as the Reference 2543, except that the 2547 is the waterproof model. Interesting that it sold for 385 CHF, versus 325 for the 2543 (which was not waterproof). I believe that the 2923 was the number shown inside the case-back for these waterproof models.

By the way, we have probably seen four or five of these Reference 2547 models (triple calendar / waterproof version) over the years, so they are rare . . . but not as rare as you suggest.

Jeff