Old myths die hard. It has been established that this jam session actually was recorded on May 31, 1955, over a year before his death. Brownie did indeed play at the same location hours before his death, but that's not what's on the recording. The presence of Billy Root makes it impossible that it is from June 25, 1956, since he was with the Kenton band at the time. Root has also stated himself that is was from an earlier occasion.
This takes nothing away from the actual music of course.
Wow - news to me. I'd always assumed that the notes on the old LP were correct..
And the notes persist in the CD still in production. You'd think Sony would add some explanation or disclaimer to the original liner notes since, in a way, the very title and concept of this album is apparently false advertising. Look at the description in the lower right corner of the current CD cover:
As already said, though, the music is still great.