Here is a photo of the remnant of the flag. The attached letter states that it was a "battle flag" but that could have been a generic discription. The size of the star and the missing white edging around the blue cross seems to point away from a Richmond Depot issued flag. The white bunting on the bottom could be the typical white border of an ANV flag or part of the white field of a 2nd National CSA flag? I lean more to the latter as the white borders were not typically sewn on using the type of seam as you see here. Not your standardized flag but likely one of a few "staff" flags?

St. Louis Dec. 27, 1865
Mrs. M.T. Andrews, Madam, I have presumed sufficiently upon my acquaintance with Mr. Andrews, to send you, by him, a souvenir of the past – a piece of Gen. R.E. Lee’s Battle Flag. After the surrender had been determined upon, the officers of the Genls. Staff determined that, that glorious old flag, which had floated in triumph o’er so many bloody fields should never be desecrated by Yankee hands. They accordingly cut it from the flag staf and divided it among themselves. The part I send you was cut off by Capt. Edwards, Assistant Ordnance Officer. I send it to you, as a Christmas gift – tis the most valuable gift I could send. I am Madam Very respectfully & c S.C. Calhoun Late C.S.A.

• Calhoun was paroled as, “Sanford C. Calhoun 22nd Georgia Infantry” pg. 69 Appomattox Paroles
• Edwards was paroled as, “Lt. W.A. Edwards, Artillery, P.A.C.S.” pg. 95 ibid – R.E.L. Krick notes in “Staff Officers in Gray” that Edwards was from Norfolk, Va. and received his commission based upon a recommendation from Lt. Col. Walter Taylor of R.E.Lee’s staff – also of Norfolk.