While the Grand Hotel recording was famously tortured in terms of the amount of time it took to get all the rights in order, and the tragic loss of David Carroll by the time they finally got into the studio, is it incomplete? I have seen several productions and know the recording quite well and can't think of anything significant that is missing.
Yes, the Grand Hotel album is distinctly incomplete--aside from lots of incidental music and underscoring, it's missing "The Boston Merger", "No Encore", and, most oddly, Grushinskaya's portion of "Love Can't Happen".