Only if you buy the physical version, however.
Nintendo games are usually free of the kind of problems that plague other AAA productions—you get a pretty complete and polished product upfront, and you never have to worry about bugs and glitches needing any day one updates or patches post launch.
However, the upcoming Super Smash Bros. Ultimate will in fact have a day one update, its director Masahiro Sakurai confirmed in his Famitsu column (via Ryokutya). The update in question will bring changes to the replays functionality, allowing you to save your replays as videos, so that they aren’t rendered unwatchable by further updates made to the game. That seems to be the only thing this update will change, so it seems like in terms of actual polish, content, and functionality, the game is pretty much complete.
The update will also be only for physical versions of the game, because the digital version will come with it pre-installed, which is good to know. Super Smash Bros. Ultimate launches on December 7. If you’re interested in the game for its World of Light adventure mode, you might want to learn about why Kirby was the sole survivor of the cataclysmic event that sets things off…