This Drip-Edge era Fender Showman Reverb is essentially a repackaged Twin Reverb, as a head and cabinet combo. This 1969 circuit is the hybrid blackface variety, which features the partially cathode biased power tubes. Internally the power cord & electrolytic caps have been changed, along with some values in the tremolo section for the sake of servicing functionality. The reverb tank and reverb transformer are changed, and the filter cap pan is missing, but it's otherwise all original.
The cabinet is not original to the amplifier, as it has blackface era grillcloth, and no drip-edge.