Now that you have seen proof that the type 3 rear band was used on Iwo let me tell you about the adjustable rear sight. My dad was a Marine on Okinawi and was issued his M1icon carbine in Hawaii. His first battle was at Perry Island in April 1944. This was the Enewetok Islands in the Pacific. Dad said his carbine that he was issued came with the adjustable rear sight. Dad was in his 80's when I showed him my M1 carbine collection. All of my carbines have type one rear sights except my Rockola which has an adjustable rear sight. I had them all laying on the floor and told dad to pick which one looked most like the one he had. He picked the one with the adjustable rear sight. I have one of every maker of the M1 carbine. All the so called carbine guys said dad was just too old to remember but I know dad knew what kind of carbine he had and I believe his did have the adjustable rear sight.