42 disc box set?!?
Half of which fans already have.... Will they release a subset that only has the previously unreleased stuff? I doubt it....
Don't you mean, "41 disks of which fans already have?"
Looking at the list, no, but it's more than half.
Discs 1-15 are all of the albums from Halford's original stint with the band (including Unleashed and Priest...Live).
16-21 are the two Ripper studio albums and two previously released live albums.
22-29 are the Halford reunion studio albums and two previously released live albums (the list skips from 27 to 29, so it's not clear what disc 28 is).
30-40 are live material from '79 through '91. Most of it is marked "previously unreleased," but I'm not familiar with any of the stuff that isn't so marked.
41 and 42 are marked as "beyond live & rare: previously unreleased stereo recordings from the archives."