Howie altered his thinking as we discovered letters in the National Archives as well as order books that stated there was a bunting shortage in the Richmond Depot that lasted until late August, 1863. This is why Lee's army did not get their Second National HQ flags until October, 1863 at the soonest.
Longstreet leaves for the West in early September so I highly doubt that they carried any spare flags as the depot was busy making flags for Ed Johnson's Division, the replacement flags for Heth's Division as well as any others that lost colors at Gettysburg on top of the HQ and depot flags that could finally be made. There would not have been any spare flags to go around until all of the units that lost colors at Gettysburg had their's replaced and Johnson's Division had their myriad of flags replaced by ANV Third Bunthing issues as well.
I don't think, and neither did Howie later on, that the Tennessee regiments of Gracie's and Johnson's Brigades got their ANV flags until they arrived in Virginia in the Spring of 1864. This explains why they fought with Hardee flags as that was all they had at the time.