Wait, did Kiba sound like he didn't know Naruto in Chunnin Exam? I remember the flashback one but you got to remind me.
I'm talking about the way he talked down to him during the exams.
http://www.mangapand...chapter-39.html
http://www.mangapand...chapter-39.html
Kiba completely ignores Naruto here even acknowledging him as a challenge, goes straight to Sasuke, and Naruto's opinion of him is not much either. And when they are set to fight against each other, Kiba's behaiour is not exactly one you'd consider that of a friend, we even got a flashback showing Naruto fail doing the henge and Kiba thinking him to be a loser.
So iit's unlikely that Kiba would have spoken to Kiba as a friend at that point, and it would't be so polite as the Kiba at that point was a arrogant piece of kitten.