Share 'Is this disc legal?'

I found a Cyclone in the woods at a park today, and there is "Property of Isabella County PKS"  inprinted onto the bottom of the disc.  I literally mean that the letters are indented in the plastic  (picture attached).  I plan on returning the disc, there was just no one at the office at this time, but would this disc be legal to throw at a tournament?  There is rule 805 B(6) which states a disc…