Bulova 1961 Bulova 23 Calendar

Cool watch indeed.Watches produced from 1948 onward are not dated by the s/n. Look directly underneath the serial number for a two digit letter/number stamp to verify date. My guess after enlarging your photo and squinting is it will be "M-" which would place it in the early to mid 1960's. I find your watch on site identified as a "Regatta 23"; the variant letter to be determined by date of production. Here is what I believe to be your watch.

With the date code off either the case back or movement, we can give a positive ID.

Going off the case serial number, most serial numbers like this beginning with E or F fall into the 1960 or 1961 date. We will need to confirm a datestamp, but this is just a guess.

For 1962 linebook and 1964 pricelist we have the Bulova 23 Calendar "B"

Later we see the linked Regatta with darker color luminous dial.

Looking at this photo I agree with Bob that the date code should be under case serial number.

Bulova 23 Calendar "B" (date pending)

I agree this is most likely a 1960 era Bulova 23 Calendar "B"

1961 Bulova 23 Calendar "B" (after jeweler confirmed date code on the movement and one is not found on the case)

Enlarging the new case back photo, date stamp directly under serial number does appear to be "M1".

Based on date stamp, 1961 Bulova 23 Calendar "B"