While a Rolling Stones 50th anniversary tour is now on the back burner, the venerable English band is exec producing an as-yet-untitled retrospective documentary, with Brett Morgen directing.Morgan, best known as co-director of 2002 Robert Evans doc “The Kid Stays in the Picture,” will have access to the Stones’ film vault and personal archives for the docu, which is set for a September release. Pic’s producer Victoria Pearman is a vet of Stones-related projects: She oversaw the 2010 “Exile on Main Street” doc “Stones in Exile” (released in conjunction with the bestselling reissue of the 1972 album) and Martin Scorsese’s 2008 concert film “Shine a Light.” She also served as exec producer of the 2001 feature “Enigma,” which was produced by Stones frontman Mick Jagger. Co-producer Morgan Neville has had a hand in docs about Muddy Waters, James Brown, Hank Williams and Ray Charles as writer, producer and director. Home entertainment firm Eagle Rock Entertainment, which issued “Stones in Exile,” is releasing the feature. It remains to be seen if the pic will get a theatrical rollout; “Exile” was screened at Cannes in 2010 and was screened on “The Jimmy Fallon Show” before its homevideo release. Doc may be the band’s major presence as they hit the half-century mark this year. Last week it was reported that the Stones had postponed a projected 50th-anniversary jaunt until 2013, reputedly over concerns about 68-year-old guitarist Keith Richards’ health.