: Hi everyone:
: I wonder if a 1153N (first execution dial, first execution hands)
: can have a cal 12 movement (the master reference table only
: lists cal 11 for this combo). Any help is greatly appreciated
: Mathias

It seems unlikely, but nothing is impossible...

Looking at http://onthedash.com/docs/ChronomaticMovements.html, the Cal 12 didn't appear until late 1971, by which time you'd expect 2nd execution hands to be the norm.
Do you have any pictures? Can you get the serial number off the case?

I have a 1153S with serial 1911xx, 2nd execution hands (and dial, I think, though I'm not sure what the differences were between 1st and 2nd execution dials), very like this one:
http://www.onthedash.com/Guide/_Chronographs/63.Carrera/e.Automatic_Early/b.Ref_1153/f.1153S_Second/
and it has a Cal 11.