While Rucker was recovering, General Forrest dissolved the 6th Cavalry Brigade and assigned component units to other officers. On August 20th he was a Colonel with no brigade, no staff and no escort. None of the regiments or battalions Rucker led at Brice's Crossroads served under his command during the last four months of 1864.
As late as Sept. 12, 1864, Col. Neely and his Tennesseans denied Rucker's authority as brigade commander. Despite orders issued on August 30th assigning Rucker to command, the issue required Forrest's personal intervention. Since his appointment caused such great displeasure among Neely's officers and men, we would definitely not expect them to have been involved in a flag presentation to Rucker during August.
If the flag was actually presented on August 20th, the only people present would have been Rucker and his well-wishers from Aberdeen. We can assume that many residents of the town became pleasantly acquainted with the colonel during his recovery. However, without some specific word from General Forrest about plans for a new brigade assignment, it would have been presumptive of Rucker to have accepted a "brigade" flag of any kind. As a wise and discerning man, he would have known better than to be involved in a public ceremony which General Forrest could have easily interpreted as interference with his authority to name brigade commanders.
Rucker must have accepted the flag as a token of personal appreciation. That would have been perfectly agreeable to all parties. Later that year the Aberdeen banner might have become a defacto "brigade" flag.