I won’t question the authenticity of that veteran’s estate but I’d be very cautious about items with USS Arizona connections. That’s one WWII ship that most people are aware of and the fakers take advantage of it.
Earlier this month I was in a casino in Nevada and I spotted an old guy with a USS Arizona cap. I chased him down to shake his hand and talk to him, and commented on the cap. He told me that he had bought it several years earlier, new, and it had become well worn over the years. He had not been on the Arizona but he was a WWII Navy vet and wore the cap out of remembrance. When that old guy dies that cap may very well make it onto the antiques circuit and fetch a good price.
It is possible to buy military uniform stuff that is new made with just about any logo you want to have embroidered on it. I remember having things like that made when I was still in the Navy. You could find a tailor shop in most any foreign port that would do it while you waited.
BTW, what’s a “folding cap”? Do you mean a flat hat or pie hat?