Stolen in 1900? What the heck is the statute of limitations on stolen gold? I doubt it is more than 100 years.
Probably about 7 years, but that just means the original thief can't be prosecuted. That doesn't mean ownership transferred to the thief or anyone taking possession subsequent to the thief. If there was a thief. I don't know one way or the other what happened here and how those coins came to be located, but I do agree that these people should have been more careful before going public with their find.
When you have the superior firepower, there is no statute of limitations.