"and the sword I won at auction was from an estate in Cape May, NJ."

Many of Prattville's early industrialists with ties to the Pratt Gin Factory were originally from New England, Pratt himself from New Hampshire. If the sword did belong to a Prattville Dragoon, it's possible that the sword made its way north after the war via a descendant or veteran moving from Prattville to NJ sometime after the war ended. Just another avenue to research....Barry