It didn't have the emblem until Little Mac was confirmed. Before that point, it had a generic Smash Bros. emblem on it.
This, and here's proof:
Oh, don't get me wrong. I was psyched to see his reveal.
It's just that it WAS a foregone conclusion at this point. Everything else about the stage screamed Punch-Out.
Although I guess a lot of people were hoping/anticipating for the stage to represent the
Punch-Out!! series, the graphics of the 'boxing ring' stage could've been changed during development by the time
Super Smash Bros. 4 officially gets released. With
Super Smash Bros. being a fighting game series, I don't think a non-
Punch-Out!! generic boxing ring stage would have been out of place in a
Super Smash Bros. game (although I'm presuming a lot of people would think that it makes more sense to use such a stage to reference the
Punch-Out!! series). Also, even if the stage 'screams'
Punch-Out!!, a stage's thematic elements do nothing to confirm a character, as evidenced by Villager (the
first fighter/newcomer of his own series,
Animal Crossing) debuting in SSB4 even though we had an
Animal Crossing Universe/stage (Smashville, complete with KK Slider cameos and background 'Villagers') spring up back in SSB4's predecessor,
Super Smash Bros. Brawl.