Second look at one part, could see the input lights going, and the knobs, and it was an Ultra.
I knew he and Mustaine were using them, but when people do shows like that, they do not always have their gig rig with them; sometimes it will be a simple rider that requires X + Y + ?? gear, sometimes even a loaner instrument! Plus, based upon past guests, IMO, the sound has never been mixed well.
And yeah... Manson was unusually ass-inine. He can be very well spoken, articulate, and thought provoking. To me, that was more like an absinthe (Mansinthe?) fueled display of, "is this the idiot child you would rather have?" I knew him (very briefly) in Florida back in the early 90's, and he is a brilliant guy. But, "public" equals "stage" to him, and reality seems to be drifting further and further for him. He has become a devolving caricature of himself. Ah, well.