About "The Real McCoy"
Last time I checked, Prohibition took place between 1920-1933. It was already around for at least 10-20 years before Probition even started.
The origin of the idiom "the real McCoy" stems from prohibition era. As a rummrunner, William McCoy ferried alcohol illegally. Transporting $8 cases of the liquor from the Bahamas to Martha's Vineyard on his ship the Arethusa, he made $300,000 in profit for each trip. McCoy's liquor was genuine imported spirits — and not homemade swill or moonshine — but imitators tried to claim their illicit drink was "The Real McCoy."
Also to point out some small little tidbits. His ship was only named the Arethusa when he bought it. He personally named it the "Tomoka"