Overall, all Confederate states did do that, but I tend to believe the Army of Northern Virginia would have turned in the most captured Union flags. Even regiments in the ANV turned captured flags over to NC, SC, GA, FL, AL, MS, etc.
Once I retire from the US. Army, I plan on taking a nice long vacation to all the Southern Capitals and asked about Union Captured Flags and find out what they have in their museums.
Again, thank you!!
Have a good morning,
Shawn Prouty