The decision Wednesday caps an unusual civil case that combined history, coin collecting and whether the set of rare $20 "double eagles" should have ever let the U.S. Mint in 1933.
Federal prosecutors had asserted that the coins never circulated when the country went off the gold standard. Most of the batch was instead melted down.
But Joan Langbord, the daughter of a Philadelphia jeweler, said she found the 10 coins in her father's bank deposit bank after he died. She said that her father could have acquired them legally, perhaps through a trade of gold scrap.
One 1933 double eagle sold for $7.6 million in 2002.