I believe this flag is a very early, company flag.
"Beauregard Rifles" most likely was the companies' name, thus I have a short list here.
"Possibles" (Companies named "Beauregard Rifles) (All Infantry)
1) 14th Mississippi--Company (F) "Beauregard Rifles"
2) 32nd Mississippi--Company (H) " " " " "
3) 4th Florida-------Company (B) " " " " "
4) 9th Alabama-----Company (A) " " " " "
5) 6th Georgia------Company (C) " " " " "
6) 1st Virginia------Company (F) " " " " "
I will continue to search for more "Beauregard Rifles" Companies. I do not believe this flag came from a East Regiment, (4, 5 and 6 on the list). So far, I believe the 14th Mississippi, just might fit the pattern, (Fort Donaldson?)
Since it was a company flag, certainly this flag was made/used early in the war. Since it does not look like any "Traditional" Confederate flag, leads me to believe that.
I will keep search, just giving a preview, let me know what anyone thinks on this interesting flag.
Have a good night,
Shawn Prouty