VERY obvious that this flag is of modern manufacture. These type flags are flooding the market.
The dead give away to this flag are the dimensions. As cloth was a fairly valuable commodity, pre 1870 flags were made from fabric and textiles not in excess of 18 - 22 inches. There would be little waste that way.
This particular flag boasted of being a SINGLE PIECE of fabric!!! Overall dimensions were 37 inch Fly Side (wide) x 34 inch Hoist (height). Impossible for an authentic flag!!
All the best flag experts and museum curators will not even look at a pre 1870 flag that has cloth exceeding 22 inches. Again, a dead give away!!
These newly made flags are beaten, brushed, dragged behind trucks, rolled in the dog kennel, shot with weapons, burned, stomped, stabbed, sun bleached, etc to "age" them.
Extreme caution is advised.