I've seen a few "legit" dealers try to score from a newbe and one even robbed himself by not acid testing a "panda" coin. Turned out it was made by Fung Gaou Brass and Coin Works.Ha Ha
No it's not right to sell a counterfeit and as you know, it's against the law. That said, no reason to sell it for less, I would have sent it in to be graded myself. There are legitimate collectors who actually buy counterfeits, for educational purposes. If I had one that good I would've simply keep it.