Don't understand me wrong - it's possible that it is screenused, it's just something not proveable.
If you keep one and believe your friend/coworker that it is a real one ..... Why not?
The other, put it on ebay, tell the truth. It was given from a guy on set as a real, but you have no proof other than being in the same business and knowing nd believing him.
Then let the buyers decide if they believe it's real. Maybe some do and pay way more than we think.