Interesting Poland's military pin / "Mennica Panstwowa"

I was recently gifted this Polish Military pin, though the previous owner knew nothing about it.

I have had no luck finding any reference to the specific design anywhere through my online searches.

It's 2 1/2 inches long, screwback, "Mennica Panstwowa" on the pinback, which I know is the old Polish Mint.

Does anyone here know anything about this piece?

Photo link:

postimg.org/gallery/1tfzsvsqy/

myvimu.com/exhibit/54707468-mechanik-kierowca-czolgu-i-dzial-pancernych-1956
desa.art.pl/?pozycja=19093

Thank you so much for your help!