So out of all the unique things I get, these have to be up there. I couldn't find any tags, or any other caps like them, except the style used by special operations personnel in the Vietnam war. These are made from what feels and looks like 100% cotton ripstop ERDL material, and has all of the properties of being original. No tags, markings, or what-not so this leads me to believe these were a private-purchase item. They could also be post-war made, so I'm not going to make up a story about how they were used by the most elite Navy Seal while carrying babies out of a burning building, but let's just say I'm definitely keeping one for my personal collection.
Buy the hat, not the story. The most I can do is with about 98% accuracy say the material is original, and these were made well.