I think he meant it. He's grateful Lou allowed him to take this opportunity. Sure it's posturing too, trying to make sure it's not that Lou has merely given him enough rope as the saying goes.
The league thought Sutter was an a$$hole - I'm not sure anyone will want Kovalchuk back if he wants to come so much. Honestly lou probably is the only person who would give him another chance - if it worked for the team. To quit the team cleanly isn't quite the same as to quit on the team while taking up valuable roster space, you know?
now enough of this Case closed until he wants back in the league after Schneider proves himself and Larsson and Merrill (et alia really) bring back Devils D!