The flags were pink or rose due to that being the colors available in the bulk dress silk purchased from Richmond dry goods stores like Watkins & Ficklin by Capt. Colin M. Selph. In fact one of the invoices states "rich pink silk."
Red was a dress trim color then and the bolts were not big enough in width to make flags. Constance Cary wrote that the three girls who made the prototypes had a dickens of a time getting good red silk for the three flags they made.
Greg Biggs