No, the force of their punches would cancel out and create a black hole within the molecules of their fists, then the impact would make the big bang look like a bang snap, and recreate the universe.

>Some years in the future, Saitma breaks accidentally the space-time wall and travels to the past
>Whw he sees his old self, he realizes only himself could be a worthy opponent
>He arrives to the top S class and uses the pseudonym Blast
>For some reason, he turns evil and only the present Saitma can stop him
>They got the most epic fight ever, breaking dimensional wall with they punches and traveling around all dimensions of multiverse
> Finally, they both dead and everyone realizes who is Saitama in reallity.
>Saitama becomes into the best superhero of all time, and a model of conduct and improvement, starting a legend
>Genos becomes into the new Caped Baldy