The Marines had requisitioned M1icon's as early as 1939 (3000/month if my memory serves me correctly), as they had already seen the handwriting on the wall - and it didn't say A3! If the Marines could have acquired enough M1's in a timely manner, there would have been very few 03's at Guadalcanal! Marines were/are tough, but not stupid.

No A3's were at Guadalcanal. There were A3's in the Pacific, in a later time frame, in the hands of grenadiers.

Jim