I have not seen the schematic for that so I don't know it. sounds interesting.
still, a LOT has changed in noise level, alone, over the years. even what was 'pro level' in the 70's and 80's is far behind what we have for consumer playback systems, now.
modern things like quiet power supplies (toroidal, as well), very low noise fet-based op-amps adn not to mention elimination of the pots and mech switches.
I have no doubt that the specs can be significantly improved by gutting and re-doing. I know its heresay to say that, but I would still keep the nice metal work and shiny knobs 
I would guess that there are probably also ugly caps in the audio path, too.
old is romantic but in so many cases, old IS surpassed by current state of the art parts.