I have been reading everything I could find on this issue, and of course came to the same conclusion you so succinctly state: Who Knows?!! I am still working on my Battle of Nashville project, but the Chickamauga project has a little more significance in that my "bubba" had a great great granddaddy that lost a leg, and a brother, at Chickamauga fighting for the 32nd Tennessee. They signed up together at Bowling Green in December 1861, were captured at Fort Donelson, and paroled at Vicksburg with everyone else. As the 32nd was off on separate duty, they missed Stone's River, and didn't see significant action (easy to say from the perspective of history!) until Chickamauga.
As he flies the typical southern ANV at his farm in Southern Tennessee (right down the road from Appleton and the last engagement there at Sugar Creek, actually!), I wanted to get him the National and Regimental flags that his people fought under at Chickamauga...which, of course, is problematic. I was about to get a blank Hardee third pattern and paint the "32nd Tenn." designation on the white circle, and pair that up with a 13-star First National, but as you say that is mostly conjecture. We do know that the 32nd's custom First National and Hardee first pattern was probably right for Donelson, but as the unit surrendered under those flags, that would probably not be appropriate for my purposes.
Now, I saw that Clayton's (Hotzclaw's) Brigade (including the 18th Alabama), that was also in Stewart's Division with Brown's Brigade at Chickamauga, lost several Hardee fourth pattern flags a couple of months later at Missionary Ridge, but would that tell us if these flags had replaced third pattern flags in the interim, or something totally different? I guess it wouldn't necessarily have that significance, right?
I also saw that Troiani's "Cleburne at Chickamauga" shows the 2nd Tennessee bearing a Hardee third pattern, but would that be any help?
Suggestions on this project are appreciated, but I guess if no one is sure the educated guess above is as good as anything!
Oh, Greg, had a question. I have seen in your previous posts that you give tours of Fort Donelson. How would I get on one of those with some of my boys (I have six, but probably only four or five would go!).
Thanks for your customary courtesy.