On Law & Order Criminal Intent, they were grilling a Vietnam vet about handguns, and one of the detectives asked, "Were you issued a Hush Puppy?", and the vet replies, "No, the good old 911!"
OK, how many soldiers (sailors?) from that era even knew of the existence of the Hush Puppy, let alone had one issued to them? It's a question that sounds informed, but would be a really stupid guess, unless you knew the guy had an unusual background. And they really couldn't get 911/1911 right?
Well, at the time it was a pretty closely held piece of information, but there were plenty of books, documentaries, movies, etc. about our spec ops missions in Vietnam over the following four decades, so it's not out of the realm of possibility that a GI, even one with no particular spec ops training, would know what a "hush puppy" referred to. I rather suspect the term was used to a vastly greater degree after the conflict (and by those with absolutely no firsthand knowledge of this type of warfare) than during.