Wasn´t Gambit supposed to be an Omega-level mutant? I thought I read it soemwhere once, but can´t find no proof anywhere. Anyone got some intel?

Usually a mutant needs to have a power that can effect matter on a sub-atomic scale.  Aside from making things glow & blow up, he doesn't seem to show any signs of being an Omega.  It's possible that it was hinted at during an alternate reality story.  Personally, I don't understand the obsession with making characters into Omega Levels.

Gambit is only an Omega level being as newsun gambit .

yep

New Son couldn't have been anything less than an Omega-level mutant. He killed Phoenix and destroyed the entire planet in his reality.

Gambit is potentially an Omega-Level mutant. However, because he was gaining so much power, he couldn't control is, so what happened is he went to sinister who, basically lobotomised him turning his power down into manageable levels. If sinister hadn't performed this operation on Gambit, he would be an Omega-Level Mutant.

Omega isn't a term applied like male or female. At one stage he may have been, and he might again one day, pretty much like all mutants (barring the individual likelihoods, like Gambits is better than most, given what others have covered). Usually most have it as a permanent status of course, Iceman, Legion, etc, so I understand that angle, but in regard to who is suppose to be and all that, in story, he could have, out of story context, no I do not think he was, would ruin the character. 

"Omega isn't a term applied like male or female. At one stage he may have been, and he might again one day, pretty much like all mutants (barring the individual likelihoods, like Gambits is better than most, given what others have covered). Usually most have it as a permanent status of course, Iceman, Legion, etc, so I understand that angle, but in regard to who is suppose to be and all that, in story, he could have, out of story context, no I do not think he was, would ruin the character.  "

" @ReVamp: I was thinking more like on your passport lol or drivers license.  
 
Barmaid: Ma'am you need to be over 21 to drink at this bar.  
 
Iceman: Ma'am? WTF lady, I'll ice you with my icicle fist of uh ice... nah just jokes, he's my ID. *takes off wig* See, all man... mostly....  
 
Barmaid: Sorry 'sir', we don't accept Omega Mutant Cards. We don't recognize its authority sorry... plus it says your 19? And female?  
 
Iceman: Awh dammit, my jig is up. Time to make like a snowball and... roll. To DC. Hi DC people, my name is Tora...  "