Other than Court and Hissing... What else would be in the box?
I can't seem to find it now, but the only evidence I've seen of a possible unreleased Blue quad mix was in a '70s Billboard magazine article thatIt is rumoured that Blue may have been mixed in quad as well, even though it was never released.
@steelydave linked a few years ago. The article had a interview with Warner engineer Lee Herschberg, who mentioned remixing the song "Carey" for quad. I suppose it's possible that he kept going and mixed the entire album, but it was never announced in an LP/tape catalog or assigned a record #.