It does not have a calibrated input attenuator. The Type 59 signal input is a pair of banana plugs.
The manual says
The forward end of the chassis has been left free of circuitry in the anticipation that a user may wish to install additional circuitry to fit the Type 59 module to his own special application.
|Deflection sensitivity||~ 1 V/Div|
|Input impedance||250 kΩ|
The Type 59 plug-in contains two tubes, total. Both are 6BA8 pentode/triodes. A triode cathode-follower buffers the input. Next is a differential amplifier made of two pentodes. The remaining triode is used as the trigger pickoff cathode-follower. The heater of tubes are supplied with 6.3 VAC from the mainframe.