erictank said:
Nope- IM 1 had Mk 1, 2, and 3, as DuneMuadDib said. 2 and 3 were physically the same, except for color and the presence of rivets on the Mk 2 and none on the Mk 3. Mk 4 was first seen at the beginning of IM2, 5 was indeed the suitcase suit, and 6 was the one with the triangle RT, powered by the new-element arc reactor (only physical differences between Mk 4 and Mk 6 are paint scheme and chestplate/chest RT - the rest of the armor is the same). Then we have the Mk 7 in the final battle in Avengers (he starts off and spends most of Avengers in the Mk 6 suit; there are many physical differences between Mk 7 and any of the others, even after allowing for the detachable booster pack).