By the look of it, I think it could be backstage at a festival and I don't think it was recorded. If that's the case, and I'm right about Calhoun, it'd be a matter of triangulating: Jones, Heath, and Calhoun almost definitely imply having Basie, the MJQ and Erroll Garner in the same place -- Joe Benjamin was more of a free agent (he was with Brubeck for some months in 1958, for instance). A candidate would be Newport '59, where Basie, the MJQ, and Garner played, but I haven't had the time to check whether Benjamin was there at all.