Oldie but goodie... the conversation is pretty funny.
i just noticed that he uses a later Op Amp big muff with the tone bypass. Damn, I just sold one of those recently. I decided to keep my '73 Rams Head instead.
His Big Muff looks like a model from 1980-81. It has the plain cylinder knobs and the tone bypass switch. It's the op-amp model or aka V5. It has two op-amps (chips) instead of 4 transistors.