Nintendo Germany general manager indicates the same.
Nintendo Germany general manager Bernd Fakesch has stated to the Neckar Chronik (translated by GameSpot) that Super Smash Bros. for the Wii U and 3DS could be releasing in Spring 2014. This is the first indication of the game’s release since, well, the special E3 Nintendo Direct in which it was revealed.
Interestingly, this is the same launch window for Mario Kart 8, which was revealed well in advance compared to Smash Bros. Nonetheless, Nintendo itself has stated that it has nothing to announce as of now. Whether this is an actual release date for Smash Bros. or not, it will be some time before the company officially confirms it. File this under the “rumours” category until then.
Smash Bros. has been seeing a healthy amount of reveals though with characters from the recent Pokemon X and Majora’s Mask revealed to be present. The 3DS version will also significantly differ from the home console version since it will feature a cel-shaded art-style compared to the full 3D graphics of the Wii U.