Okay, this is weird... I left one of my test towns installed on the Wii for the last couple days. This town has WC24 disabled in-game (but not on the Wii). I went to inject the red Pikmin and discovered that the content had already been downloaded into the save file, nevermind the fact that this town has never come into contact with the DLC.

Perhaps it was sent out already via WC24, but not yet officially sent to us by Nintendo? Or is this a side effect of me using Savegame Installer/Extractor to use like 5 different towns on my Wii? Can someone who hasn't come into contact with the item yet try to add it to their inventory?