The Army's first pattern utility shirt was standardized in 1958 and replaced the near identical utility jacket. It was made from olive green (OG-107) 8.5oz cotton sateen and boasted two patch pockets with straight cut flaps. The shirt also had an unusually low first button and no button cuffs.
Designed to be loose fitting, it was typically worn over a white T-shirt and was tucked into the utility trousers. Though the lighter and quicker drying Tropical Combat Uniform had been developed in 1962, three years prior to the introduction of U.S ground troops in Vietnam, the utility shirt and trousers were still worn by infantrymen early in the war.
1. Military Specification MIL-S-3001C. (17 October 1958)