I assume you're referring to making a HD version of FoD? In which I'm certain if it returned it wouldn't be updated. Unless you mean adding brand new stages in as DLC in which I can only point to the Miiverse stage, which is/will be new.
But really I don't think they would have fully prepared much, if any, DLC before release. But that's just me chosing to believe their word about it.
And the 3DS version data file shown us months ago that there is a next button for the stage selection. I thought it'd be so you could design stages on the Wii U and import them to the 3DS version, but that's not the case, so either it's for future DLC or it's one of very very few competely unused data files in the game. ~ Seeing as most other unused 3DS files are used in the Wii U version.
(We also know there are atleast 4 songs unused so far in the Wii U version - 1 or 2 relate to the tournaments, another 2 presumably for the Miiverse stage.)