Here I find some information:
http://www.vintage-watches-collecti.../omega-seamaster-calendar-capped-bumper-1952/
Along with the strange discrepancy surrounding the serial number stamp on the movement, there is another even more obvious odd aspect to this watch. It will be noted that what should read “Calendar” on the dial is actually incorrectly printed as “Calender”.
This is absolutely fascinating, particularly when we consider that this dial is categorically all original and exactly as it left Omega when new. How could such a glaring error happen ? Our first reaction was that this watch was produced for a market in which the word calendar was spelt as calendar, in much the same way that Americans use the spelling color instead of the British colour.
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