Here is a (소위) Junior Lieutenant Collar tab. Made out of light aluminium with the "usual" Korean pinback. Surprisingly not made to be sewn on. Quick promotion or short term job? Who knows?
Maybe it was used on a field/work uniform, or civilian clothes...
There's nothing in the streets
Looks any different to me
And the slogans are replaced, by-the-bye
And the parting on the left
Are now parting on the right
And the beards have all grown longer overnight The Who, Won't get fooled again
It makes sense being a "tab" for the arm rather than the neck, I'd have no problem having it on a collar but someone a foot shorter may be uncomfortable.