Sometime in 1976 Columbia Masterworks went single inventory for their quad releases, so this one, along with any of the others (you can see a list here) should maintain the SQ encoding.
The issue wouldn't be with "digital remastering" (any analog tape reissues on a CD has been digitally mastered or remastered by definition) it's more what's done during that remastering process. I think the SQ encoding can survive a lot of that (EQ, noise reduction) but something like narrowing of the stereo sound field (ie mixing the left and right channels together) probably would have a detrimental effect on the SQ encoding.
That Three-Penny Opera should be good though, it's a Don Young quad mix, and probably one of his final ones too - kinda wild to think he did this and Bob Dylan's Desire in the same year.
i think maybe Annie was one of the last released Quad mixes he did for CBS?