Musicians Roadhouse

I got an old video of Judas Priest playing in Dortmund on a show that was recorded in December of 1983. On that show they played split Channel Marshalls don´t know if it was 2205 or 2210 amps. I got two different schematics of this amp. an earlier that has the master volume after the phase inverter valve. And a later that has the master after the tone stack. I wonder if anybody at Marshall knows wich of these models Judas Priest used in 1983? I´m not sure when Marshall changed the circuit.