Card fronts depicted a black-and-white photo about the celebrated military unit, usually of the men training, of pieces of equipment, etc. At the bottom was a light-green border containing: the card title and a brief caption explaining the photo; a small cartoon head shot of a Green Beret soldier; and a small green square giving the card number and set title. These last two were highlighted in bright green ink.
Card backs were color puzzle pieces.
Card #66 was a checklist; card #1 was a photo of the late President Kennedy.
Given the nature of these photos, and the tag 'US Army Photo' at the bottom of each card front, the photographs used in this set were almost certainly promotional pictures taken and distributed by the military. That doesn't diminish their value, but it does explain why we don't see photos of (for example) a Green Beret team under heavy fire or burning down a suspected insurgent village.