Hmm, at first glance, his rating is pretty low. But he made a total of $124. I am guessing this is because he was an early adopter of topcoder and they gave out prizes easier back then. I think this probably is the real Zuckerberg because of the usage was so long ago (2002).

I have not looked further at his code for more clues, but it would probably be interesting to delve deeper.