Executive Order 6102 (1933) and the Gold Reserve Act (1934) made owning or trading gold a criminal offense and required American citizens to sell their private possessions of gold (with limited exceptions, like wedding rings) to the US Treasury. The US Government instituted this policy to help the country weather the Great Depression and did not relax it until 1964.
Despite this barrier, OSS acquired gold coins to cache in Europe and retrieve as needed to finance their efforts or those of the Nazi resistance. Although the coins were not legal tender, their inherent value ensured their usefulness. OSS never distributed this one.