As has been pointed out, it's a silver "round", not a coin. It wasn't issued by the US government, or any other government for that matter; it's purely a privately struck medal. The guarantee of weight and fineness is only as good as the company that produced it (whoever that might have been).
If it really does contain the 1 ounce of silver it claims to contain, it's only worth bullion value; however, you might be able to find a Merc buff who'll pay a slight premium for it, as a novelty.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis