Lol that doesn't make any sense.
So Piccolo is all like "omg even Gohan lost in one blow, he gotta be a god, that's the only explanation !" after seeing Buu trolled first, yet Gohan wouldn't be ultimate ?
No way. Especially not coming from Piccolo that has called out Gohan's weakness every time he could.
As for Gohan's looks, the only reason the bang is back is nostalgia and because it's basically the same hairstyle, just "scruffier".
The bang was never part of the transformation, it was his original hairstyle to begin with.
They did the same thing when Trunks went USSJ in Super, gave him the same old original hair... Except the only reason he had that hair in the original was because he had long after following the HTC, that wasn't the transformation giving him long hair.
Gohan's Ultimate aura is similar to his base aura. so it's hard to tell base off of that. In BoG he didn't have a bang though, but we don't know if they intended Gohan to have a bang or not in BoG to represent Ultimate.
In the movie he had the bang before transforming just by changing clothes, and in the Trunks saga he had the bang without ultimate.
The bang is kind of irrelevant regarding anything that preceded the current arc.