Here is the tweet for your perusal:

To be honest, it sounds more like a rap lyric than a Lebron James diss but maybe Dan was taking a shot at the idea that people with procure wealth under a-hole pretenses will always be a-holes.
Sure, Lebron could be considered along those lines but coming from a man that loves comic sans, Gilbert probably has a little more flair than that. If he wanted to diss Lebron, he probably pull a George Plimpton and diss Lebron with each letter of his tweet spelling out, "You Suck Lebron".
Oh well, I guess in the end we will never know and for now we will have to let Twitter bygones be Twitter bygones.