I'm the guy that digitized and propogated this particular set (you got if from the Jazz Vines group, I assume?). I got my info from the Bregman discography, but now I see that I dropped the July 14th date (same as on the webpage cited) due to a page break and my own inattention. Bregman does not cite any commercial releases, but his book is copyrighted 1993.
I got it on cassette tape as a gift from a friend, a very experienced collector. The sound isn't too good, but hey, it's Bird, right? I think the real value in that pair of cdrs is the interviews, especially the blindfold test.