A Ceriatone clone of it with a Mercury OT for $1700 would slide right on thru a blind A/B. Just sayin'....
But it is a cool piece of history to those of us left that still care about that sort of thing.
According to Ken underwood, Marshall never made any prototypes, they couldn't afford to. There certainly weren't 6 of them. Not having watched video, I call foul.
This may well be a very early JTM45 granted, and a cool find but that part I do not buy.