I was researching at Western Reserve Historical Society in Cleveland, OH last week and came across this item in the large William Palmer Civil War Collection there.
It is a letter from CS Gen. PGT Beauregard as commander of the 1st Corps, Army of the Potomac (as they were called then) dated September 11, 1861 asking what to do about the flags captured at First Manassas. The letetr contains these flags:
1st flag, 69th Regt. NY on staff
2nd flag, 2nd Regt NY, short staff
3rd small flag on short staff (probably a guide or flank marker)
4th regimental Federal flag without staff
5th 4th regimental flag with cord and tassel
6th 5th Federal scarf
7th 6th flag abandoned at Fairfax and sent by a lady
8th 7th flag captured by Corp. Dutart 2nd SCV
9th 8th flag shot down at Fairfax C.H.
10th 9th garrison flag and halliards
II. one arty flag in a bag
Sadly the last flag is cut off as Beaurgard's signature was clipped off by an autograph hound at some point. The reason the number change part way down is that flag 4 is crossed out as are the original numbers to the left side. Who knows what happened to this flag.
Anyway - hope this was of interest.