For the Shout remaster they got Dean Cundey to supervise (or at least approve) the finished transfer. They used an IP source, which is probably why they settled for 2k. I’m not sure what film elements were used for Uni’s hd master, if that’s even knowable.

The main issue with Shout’s release (and IIRC this was also a problem with the most recent Halloween transfer, which was also supervised/approved by Cundey) is that the color-timing pushes everything too far towards the cool end of the spectrum. A regrade using the old bd’s colors, which seem to more closely resemble those of a 35mm print, would seem to be the ideal combination. Maybe Arrow’s 4k job will end up being exactly that.