If you are convinced it is .999 silver, and you can convince a buyer that it's .999 silver, then it's worth whatever the weight is. Being a privately minted medal there's little collector demand.
The Numista example of this medal linked above is made of "nickel-steel". Since base-metal examples of this medal exist, I would recommend some skepticism. The steel ones can probably be filtered out using a magnet - if it sticks, it's not silver.
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