For the last year we've had Nintendo World Championship Gold in our database but it has never shown up on the website because there were no recorded sales that we knew of. I have since verified two sales for the NWC Gold cartridge in private transactions. They didn't sell on ebay, but between two collectors directly.
We added these prices to our database for users to see and track because Nintendo World Championship Gray cartridge is the most popular game on VGPC. I'm sure people want to know the prices for the much more expensive and coveted gold cartridge too.