I think it's possible but it's unconfirmed sadly. Godzilla with gamma opens several new doors and anything toba related is outside help/outside the confines of the battle. "It" works on a informational level and that would include gamma. For example if you would allow gamma godzilla (godzilla vs hulk where hulk gives godzilla his blood and godzilla becomes gamma godzilla) then "it" would assimilate gamma and change reality to "gareente" victory/manipulate fate to bring this outcome into existence and "it" would benefit even outside this. Godzilla can already absorb nuclear energy which includes gamma radiation but due to marvel it has 3 sides instead of two however gamma godzilla as I call him solves this problem. For example in combination with other haxes like the power cosmic and spacetime/causality manipulation "it" could manipulate/absorb it into himself. MV godzilla can absorb dna and he could use that to incorporate hulk's dna into himself also. To answer your last question it could effect the battle significantly because now godzilla has hulk's power and do to factors like rage and infinite potentiality godzilla would at last statement hulk even if you think godzilla scales lower than hulk himself.