Happy New Year!
And yes, this desk was built way before phantom power became standard.
A little late to note, but they used a color code on the buss bar pins, as I recall red is to a buss resistor and white is straight to / from the buss
When I was there in the 70s there never were any phantom power switches. A desk could be fitted with phantom power which would be wired directly to all mic input XLRs. Phantom power was supplied by a single module that contained a simple switched mode power supply that that doubled up the 24V dc supply. Nobody worried about non-phantom powered mics being connected to mic inputs with phantom power.I remember going to the first session at the Who's Ramport Studios with their new Neve console which I designed. They miced up the drums and monitored the result but it was terribly distorted. We discovered the phantom power supply module had failed. So me and their tech removed it and hooked up a bench supply to the the connector so Roger Daltry's first solo session could go ahead.CheersIan