There was a flag labeled as belonging to Shelby's Brigade that was displayed in the Confederate Room of the Oklahoma State Historical Society's Museum. Since the museum has moved from the Wiley Post building I haven't visited the museum to know if it is currently on display or in storage. The historical society's web site is
http://www.ok-history.mus.ok.us/. It has been a few years since I was an intern there, so I'm not sure who the best person to contact regarding the status of this artifact.