All 3 of those look the same to me, aside from proportional differences. Even then, the model that Mega Man has in Smash 4 is unique to Smash 4. It doesn't quite match his promotional art, nor does it match his in-game sprites. It takes his design from the promo art and changes the proportions slightly to fit his in-game sprites. He's basically MM 7 & 8 Mega Man with animations from the rest of the games.
Anyway, my point was that Sakurai didn't design Mega Man to look like he "originally" did as you were suggesting, only because how he originally looked is the same as how he looks now ("now" being his most recent game).
I hope this post isn't confusing, it's hard to explain what I mean.