If this is something you are legitimately concerned for, you can get high karat jewelry in different forms like a chain, that was not confiscated. Also, doesn't mean you have to report it or turn it in. If purchased local with cash, there is no record, you can also have it stored internationally. Forget the amount but you were allowed to keep a few ounces I believe. Silver has been massively demonetized and is more of a industrial metals play while gold almost all monetization.Gold will be illegal to own, you'll be curved into selling at a price point of their choosing, the legal precedent is already set almost 100 years ago, it's there, it's always been there.
Buy silver instead.
Personal opinion is I highly doubt this happens. The world is a much different place than 100yrs ago and there is a lot less patriotism now which inclined people to turn in for the overall benefit of the country.