Could be fake, I mean, you can easily replace the statistics with an edited picture of it, while having the other elements playing making it look legit. But I don't know, I'm not on Xbox to see him on the leaderboards.
There is a exploit on 360 that you can modify stats and prestige. I'm not sure if it is public or private; it is possible though through USB (without modded patch).
For the ppl saying that him getting 9001 kills and 0 deaths isnt legit and that its fake the guy means that him having a challenge lobby is legit not his stats :dumb: