If it is a trials item it will say "TruVsu" or "Truppenvesuche" on the label followed by the date. There's another term used on some labels, but I've only encountered that once and can't remember what it is off the top of my head.
The Chinese made knockoffs when the uniforms were hard to get a hold of. They are stiff and made from 100% cotton (IIRC) instead of the cotton/poly mix of the real shirts. I've got some of them sitting around in my basement. They're pretty good copies including faked tags, but it's easy to identify. Post some pics and I'll be happy to take a shot at identifying it!