Partial uniform items like fatigue shirts even devoid of rank and squadron patches, were banned from on base facilities. Off base partial uniform items were forbidden period. One exception was footwear.
I find it hard to believe now, that any branch of the military would allow, much less encourage, wearing uniform items out of context.
Considering anyone can buy anything online my first thought when I see someone in public wearing a uniform is grooming standards. The guy in this story wouldn't pass that test.
The next thing I look for is patches and awards and decorations. Anyone in a combat uniform wearing medals (particularly miniatures) is almost a dead give away as a poser. Usually, they also have four or five rows too, all in the wrong order.
The final consideration is age. A young or old person wearing they wrong type of uniform also screams poser.
This guy was a Warrant Officer according to the SF guy with me. He had the same basic decorations as my dad and my dad was a Secretary in WW2. Nothing elaborate but it was just weird.
The closest other thing to a uniform there was a Vietnam Vets cap.
My FIL “lost” his uniform after WW2 under the impression that you couldn’t get sent back overseas if you didn’t have a uniform. Big mistake.