Greg...
... has been awhile, will go and try to retrace. Hagoods South Carolina Brigade was the primary on the ill fated counter attack that took place on Aug 21st at Weldon RR. However there was significant fighting the day before on the initial thrust to reclaim the RR that included Mahones Brigade and a host of others which I think included some of Johnsons troops... but will need to recheck it. If I recall I believe I found that in a battle report of one of the federal units participating mentioning flags they had taken there with passing comment that one flag had a blue field with a plain white "moon" or "disc" in the center as they described it.
Frederick