Leesa - to answer three questions you asked in the thread above. Yes is is a 1965 model, on that point there is no dispute. Occasionally we find watches that have a different date code on the movement than the case, we like to argue those. 5AT is the model of the movement, without going into too much detail it represents the physical size and complications (options) of the movement. Lastly, regarding the number of variations to the La Petite line, we just don't know. Everything we know about this wonderful brand is 'found' knowledge. Bulova lost all records prior to the 1970's so we are slowly rebuilding the knowledge data base one 'found' advertisement and watch box / hang tag at a time. We might not nail yours down to a model / variant for a week, a month, maybe longer, but we'll never stop looking! Oh, one more thing = 2303 printed in the case back is the STYLE number of the case, we just don't know (yet) what name that matches to.
In the mean time, enjoy your wonderful family heirloom!