Not sure about on a RKing, but it might look cool on a Fat Boy depending on the wheels & paint scheme.

 

Looks like they tried to make a RK look somewhat like a Cafe Racer. No way will it keep anything off you and it dosen't do much for the bikes looks. Isn't the reason we all like the RK for their Classic look and appeal. If I wanted to ride behind a faring I would buy a full Dresser. I think they are a fantastic looking ride but I prefer that Classic Harley look for now so I'm sticking with the stock windshield.