If anyone is in the Valley, stop by the museum at New Market where they have displayed a similar conversion, in this case a pre-war VA militia flag cut down and the center device used as a canton for a First National. The three bars were assembled from a disassembled US Stars & Stripes--all silk and well sewn. They even display a photo circa 1910 of the lady who made it, holding the flag (can't recall the unit).
Josh