Just the year before, Keeler, a 21-year-old sergeant in the Army Corps of Light Infantry, had been presented with an engraved, French-made battle sword by no less than the Marquis de Lafayette.

A rare Paul Revere-printed “Sword in Hand” note, held in a private collection for over 30 years, shattered expectations at Heritage’s Winter U.S. Colonial Currency Showcase, far exceeding its $1,500 ...