EXCLUSIVE: Old rumors about the storied rap label may soon be laid to rest and, in some cases, confirmed, as music and film producer Damon Dash has partnered with Preachers of L.A. executive producer Lemuel Plummer to tell the story of Roc-A-Fella Records, the label co-founded by Dash, Kareem Burke, and rap superstar Shawn “Jay-Z” Carter in 1996. “It means a lot that Damon trusts us to tell the story– the true story –of how two global music icons got their start and did…