: Would appreciate if anyone can help me. Did the 1158 come with both
: the calibre 11 & calibre 12 and if so when did the change
: happen? It seems most of the watches have a Calibre 12 movement
: so wanted to check if the watch I am looking at is genuine given
: it has the calibre 11 movement. Any help appreciated
Yes, it came with both. Putting a date on the changeover is tricky - I saw some technical drawings for the Cal 12 at La CdF that were dated Feb '71 so we have to assume it was at some point after that.
What are the first three digits of the watch you're looking at? That will help in dating it.