Even if they were stolen, isn’t there a statute of limitations?
There may be a statute of limitations on prosecuting them for theft, but AFAIK there's no statute of limitations on seizing the stolen goods and returning them to their rightful owner.
Sounds like it the government’s case to prove they were stolen, i.e. that absolutely none of them were sent out for circulation. It will be the heir’s burden that the coins were obtained legally.
When the hyper greedy, rapacious federal government wants what you have, there is no statute of limitations or protection. That the country bequeathed to us by the Founders has been reduced to this by generations of disgusting politicians from across the political spectrum with barely a whimper from the people is beyond tragic.