I've been looking over photos of WWII for the past year, specifically looking at carbine configurations. I have yet to see a picture of the battle at Iwo Jima (Feb-Mar 1945) that showed a carbine that had a Type II sight or a Type II or a Type III barrel band (with lug). As far as I can tell, the first appearance of those two items in Pacific theater combat appeared in the battle at Okinawa with the Army troops. The photo referenced above does not have a date, but in that it shows a B29 landing on Iwo Jima it could be anytime from Mar 1945 to Aug 1945.
Also, the earliest I've seen a carbine with the Type II rear sight and Type II barrel band in the European Theater was February-March 1945. The most common configuration is Type I rear sight, Oval-cut oiler slot, high wood, and Type I band. I haven't looked for safety configurations as it's generally hard enough to distinguish the barrel band and high wood versus low wood.