Mel.. this is an old story.. well known in the coin hobby
for the uninitiated, the coins were never legal tender because they were not legally released by the Federal Mint. Most likely, a managerial employee pocketed a few and was able to get them out of the building before the entire stash was melted down. Possession of them is illegal and the old coin dealer knew that which is why he never announced his ownership of them while he was alive.
There is an old law: stolen property cannot be sold because you cannot authoritatively transfer ownership in something that doesn't belong to you.
ergo, the Government is the proper owner of the gold, and he who has the gold makes the rules.