And many who were issued carbines also got their hands on a .45 pistol when they saw the general ineffectiveness of the carbine.
They must have been REMFs. My old man was a battalion armorer in Korea. He was at the Pusan Perimeter. He didn't have enough M1 and M2 carbines for the officers that wanted one, and several of them tried to pull rank to get the M2 he carried. Most of the officers already had a 1911.