Well Prince-Luigi played like 20 hours a day until he reached 56. Anyone who was playing at that time watched the progression of his xp. The sanity of playing that much is another question, but he is 100% legit.
The "second" profile you speak of was a hacker who usually goes by the name MLG-Zaraki (formerly iWinAgain/OG), but would alternate names to mess with people, such as Prince-Luigi, Prince-Mario, Prince-Yoshi, etc. The two people do not know each other at all. Many good players have imposters, currently Oaky[SD] and CrazyBaconSD both have people impersonating them. The real Prince-Luigi is the top legitimate player xp wise. I never commented on cure for cp since heck if I know who that is.
Also in regards to "Wait. You run a Goldeneye site, and haven't heard of (apparently) the greatest online Goldeneye player?", which player are you referring to?