I think (bigger than 50% chance) that I recognize the seller and the origin of the
machines, and I think it's very likely that some of the machines have some specialized
communications hardware that was for some period very hard to get at and may even still be
worth considerable $ to those in need of it, if the cab kit and remote mux distribution
panel is present. But to anyone outside that industry it's very unlikely the board
itself would be considered wanted at all, and I think it's 99% likely that the seller
is not including the remote mux distribution panel, it often gets trashed in the
"decommisioning".
It's a little sad to see machines "parted out" in a way that separates the
Unibus backplane board from the part of the peripheral that's actually needed in
industry, but this "parting out" phenomenon is so widespread on E-bay and those
who do it tell me that it's the only way to make money. So PDP-11's get chopped
off the actually interesting and valuable system they control, and as a result neither end
is desirable by itself.