This Bassman is presenting itself incognito, as it appears to be missing it's "drip-edge" aluminum trim (most likely removed by a previous owner). Though rest assured, this is the real deal Blackface transition amp, as you can see from the black lines on either side of the silver face. The tube chart says "AB165", but this is in fact a hybrid version used very briefly from late 67-68, which features a partial cathode biased power section. These are rare amps, and it translates well into a unique sound, very much a progression from the mid 60's era, as compared to the less desirable designs of later CBS.

The circuit components are all blackface, featuring the "blue molded" Ajax coupling caps that define the sound of 60's Fenders. The power cord, bias cap, preamp electrolytics, and one power resistor have been changed, but the circuit is otherwise original.