3D Graphics and Game of Go are both failed beta sites. I would not expect them to show up in the /sites list - but they do. Indeed, attempting to list questions on one of the sites fails:

http://api.stackexchange.com/2.0/questions?site=go

{
  error_id: 400,
  error_name: "bad_parameter",
  error_message: "No site found for name `go`"
}