No video preservation that I know of has the full 70mm audio, since no preservation has the 70mm video. Even then, we’d be talking mono tracks from in-theatre recordings or reconstructed from the 8mm digest. It’d be pretty ugly, although maybe possible if you wanted mismatched audio badly enough.
Didn’t morgands1 preserve a tape recording of The Empire Strikes Back from a 70mm showing in 1980?
EDIT: A recording of the audio, not the video.