Sounds like it could be a 349.

Here's a catalogue shot showing one from the post-war period:

It sounds from your description, though, that the numbers are not "cut off" by the chronograph registers. If we go even further back in the mists of time to the pre-war years, we find that there is a 349 in those catalogues too, with smaller numbers on the dial:

So that seems a possible candidate. These older chronos aren't my speciality, but it feels like we're getting closer at least. We still need a photo to be sure(r) though!

Mark