Judd J-33 is a so-called "transitional" piece that marries a pre-1860 With Stars obverse with a post-1859 reverse. The result is a coin that lacks the name "UNITED STATES OF AMERICA" on both sides. Thus, it is unlikely that this is a legitimate pattern because it never stood a chance of being considered or accepted for general coinage. Nonetheless, it is an extremely popular coin, whose notoriety has benefitted from an understatement of its true rarity. For years, PCGS listed the mintage at 12 coins, but the sheer number of auction records since 1994 indicates that at least two dozen, and possibly more, are known.
Cameo examples exist, but they are very rare. The Simpson PCGS PR65CAM is one the finest examples known.