I think a lot of people are getting a bit confused here, or maybe there are multiple ways to unlock a costume. But from what has been said by other individuals on this thread is that there is a Godfall Superman skin and there is a Prison Superman skin.
Both have at one point been rumored as being the unlock for beating the iOS game, and others have said that you can unlock one of them by beating the console story.
I believe the Grundy place holder people are referring to is know as Alternate Universe Grundy, who we suspect is the placeholder when you triplicate lower tier cards, and there is Superman Prime, a placeholder for higher tier cards.
Theories range from these being unlock-able on console, unlock-able on the iOS app, future skins or just convenient labels. Our hopeful theory is that in future the iOS will be updated with more levels and characters, netting us more potential skins, which would makes sense from a business standpoint as most have spent some money on the game. Plus by playing the console you unlock money/character cards for the game. Also the placeholders seem to go up to level 88 and promotion lvl VII, but it has been theorized that this is because in code 8 can form any other number.
I think that's it...