Shirt:
Shirt’s cut is identical to the earlier standard issue US OG-107 sateen utility fatigues (Samples 1 and 2 on that page), except in a khaki tan twill material. A similar jacket was once available for sale here: https://communitythriftandvintage.com/products/vintage-olive-cotton-canvas-jacket.
Stamp:
Contract string is “DA 92-557-FEC-14297”. “FEC” likely indicates it is related to the US Army’s Far East Command. Contract numbers with “FEC” and a similar format were issued to various Japanese organizations during the late 1950s to the early 1960’s for things as varied as labor on bases and scientific research (source: https://books.google.com/books?id=_Tg2AQAAIAAJ&pg=PA171&lpg=PA171&dq=DA-92-557-FEC&source=bl&ots=_5QKiUq4PB&sig=ACfU3U3ytBAf383HnlSc4UtRvwRiQVDBEQ&hl=en&sa=X&redir_esc=y#v=onepage). The “DA” contract prefix was used from 1953 – 1961 (source: https://www.armynavywarehouse.com/post/contract-number-dating).
Collar and Shoulder:
Cuffs:
Inside:
Manufacturing error on bottom hem.
Cuffs:
No buttons on cuffs.
Buttons:
US style bakelite (?) button.