I have one with the AA165 stamp sitting right next to me. Still alive & well! Can send pictures for you to admire 😉 hehehehee

I also have a 1965 Bassman with the AA165 label, however it was made in November of that year and has the AB165 circuit. It is true the AA165 were only made from January to March 1965 then Fender switched over to the AB165, however they made many, many tube chart labels for AA165 which they used through out the year until they ran out and ended up in many, many AB165 circuit Bassman’s. Fender never wasted a thing and kept poor records so there are many instances of inconsistencies from tube charts to guitar woods. I cannot speak on the 1966 Bassman with the AA864 circuit that was only used in the Blonde Bassman’s of 1963 which features a presence knob and lack the extra gain stage in the guitar input. Either it is a total fluke, which is highly unlikely because we are far into production by 1966 and CBS has taken over… perhaps there was a modification at some point in its lifetime to revert it back to the Blonde circuit that people do love.

I’ve got a ’65 Bassman with the AA165 circuit and the AA165 tube chart. It was made in April of that year – stamped OD – and it is wonderful! Turn it up all the way and it sounds amazing. I’m not sure about your research source but here’s proof that they exist.