I was just looking back over the manga and their first "real" mission that the Hokage assigned them was suppose to be a C level mission, but in reality it was an A level since they had been attacked by Haku and Zabuza?
I also looked at the end of episode 69 where a sound nin is looking at Naruto's nin-info card and it lists:
A level - 0
B level - 0
C level - 1
D level - 7

Meaning that the Zabuza mission was a C level? or that it was just recorded as that and it was really an A level mission?