Even if it's the real deal, Nintendo wouldn't be dumb enough to let slip something as big as a WiFi sticker this soon, if they plan on keeping that as a surprise. They can always add the sticker down the line, around the time they'll change RP to whatever rating this gets.
About the design, this one definetely looks real, as in not a montage of publicly available screenshots. The lighting is perfect. It may not be the final design, however, as we know from Mario Galaxy.