Thanks to @nickschiavo who sent this to me. I asked him to source it, and he pointed me to the St. Lucie Mets website.
I’m sharing the screen grab in context so you can see that other Mets hats including the 2014 Memorial Day cap are listed. Makes me think this is the Real Deal like Matt Harvey.
I can’t remember if Memorial Day is part of Stars and Stripes of if we’ll get yet another cap then (I think last year they were two different things.) Anyway…this exists in case you ever want to represent the Mets while simultaneously partially hiding from the enemy in the desert.