McCain is a member of the CFR, so probably. He is confirmed not to be a Freemason (by the Freemasons), however neither was Reagan, and and he attended (so Masonry has nothing to do with it / membership is not a requirement). Also, Freemasons must believe in God, so it is possible that Freemasons can't also be Bohemians.
Unlike Obama, McCain has not been seen on TV during this years convention (July 11 - July 27).
The Bohemian Grove is Republican only, and all male. It is rumored to be Whites only, but I also heard an Asian was seen once in attendance, possibly as a "guest".
McCains father attended.