In response to the recent news of the theft of error coins by a Mint police officer, Tom Jurkowsky, director of the U.S. Mint’s Office of Public Affairs, issued a statement clarifying the Mint’s position that error coins leaving Mint legitimately are legal to own.
He stated that, "Error coins that are lawfully issued — coins that were not detected by humans or machines — belong to whomever has lawful possession of them. The United States Mint strives to achieve only the highest quality of coins that it produces. However, we as humans — despite our high professional standards and use of exceptional machinery and equipment — occasionally make mistakes. While rare, coins containing errors have legally left our facilities. As long as such coins have been legally issued (e.g., numismatic coins sold to collectors who purchase numismatic products, or circulating coins sold to the Federal Reserve Banks), they may be privately owned. We do what we can to minimize those occurrences and pride ourselves on the very low number of error coins that do, in fact, find their way into circulation or into our numismatic products."
Here is a link to the Coin World article:
U.S. Mint clarifies ownership of error coins