You didn’t mention Vietnam but the usmcpress.com mentions the American flag being part of the “new” Chits during the Vietnam era:
During the war in Vietnam the fighter, attack, and helicopter crews carried new blood chits. These chits displayed the American flag, plus an appeal in 14 languages: English, Burmese, Thai, Old Chinese, New Chinese, Laotian, Cambodian, Tagalog, Vietnamese, Visayan, Malayan, French, Indonesian, and Dutch. The wording in each language was the same:
I think he got out before VN.