Later this month, Cherry Red’s Turtle Records is turning back the clock almost 50 years for the first official release of two 1969 concerts from longtime friends and collaborators Michael Gibbs and Gary Burton.  Festival ’69, due September 28, is a 3-CD set of performances from Gibbs at Lancaster University (February 1969) and Burton with Gibbs at Whitla Hall in Belfast (November 20, 1969) primarily featuring Gibbs’ own compositions. Students of Herb Pomeroy, trombonist Gibbs and vibraphonist Burton met while attending the prestigious Berklee College of Music.  Burton’s early fusion records on…