They are live versions from a 1967 set at the Fillmore with Grace. Unfortunately on some of the Fillmore '67 performances at the end of disc one the guitars are out of tune.
The mastering on the box set is similar to the late 90's/ early 00's Airplane reissues.
For me the best part of the box set is the inclusion of stereo fold downs of material from the Quadraphonic issue of Volunteers that used entirely alternate takes.
"I know it's hard to defend an unpopular policy once in a while." - Zappa