Thanks, Gerani53, but, no, a 3-negative recombine is not the same element (or source material) as an interpositive.
In the world of film elements, the original camera negative (that is, the negative that actually ran through the camera and recorded the original image) is the original source for...
Unfortunately, with many films, this is the case. The only film (that I know of) in their Hitchcock series of UHD releases that also has the newer transfer on the included Blu-ray is "Psycho" — And that is the only one that I have purchased (and the Blu-ray looks fantastic).
I'm still assuming...