Song is Blues in Hoss' Flat by the Count Basie Orchestra. This is the same version as the movie, except in STEREOsome remixing for instrument clarity and separation. It is from the 1958 "Chairman of The Board" album, and "The Errand Boy" is from 1961.
Eddie Jones Bass
Freddie Green Guitar
Sonny Payne Drums
Count Basie Piano
Joe Newman on the trumpet solo at the end.