14k gold case 23 jewels.
The Bulova Model price list for Fall 1958 doesn't have any Regatta models listed in either the new or updated sections. By Fall 1961 there are six two-letter variants in the Bulova model price lists. Thinking if this is a Regatta 23 rather than a Bulova 23, it must be the first year of the Regatta.
The first year we see any Regatta ads in the main ad database is 1962.
Do any new newspaper ads suggest the Regatta came out in 1959?
...just seeing we don't have any confirming pictures or date code symbol for subject watch production date...only the year entered by owner. Incomplete record. PM sent to owner for possible update.