I believe that you have answered your own question ($500) but the value of gold has gone up a bit since 2012 and some investors may pay more for it expecting the value of gold to go up so it may be worth more than $500 but only a bit more.
The coin contains five ounces of pure gold and only 146 were minted. Aside from the $10,000.00 in bullion value, it must have some numismatic value.
I believe the value is about the value of the gold. Probably a thin market of folks wanting it just to collect.