No they're not. It was made clear that they experienced different life events, owing to Nero arrival, resulting in different people.But...they are representing the old characters.
Name just once "old" Kirk open fire on a defenseless enemy ship, because the Captain refused to surrender. Oh, and trying to drag Kirk over the side of a cliff doesn't qualify as "defenseless."[Chris Pine] doesn't disrespect the character of Jim Kirk with his new interpretation of him.

But they are new actors playing the same characters, albeit with different life experiences after 2233. But that's to be expected since Kirk in the new timeline grew up without a positive father figure...he's more of an angry and cocksure fellow than he was in the original timeline. Quicker on the trigger because he's no doubt more cynical because of his rougher upbringing. I can swallow nuKirk because of those facts. He doesn't bother me in the least. The same might happen to any one of us if someone changed our past histories in a negative fashion. 


