Does Buggy the clown know where the One Piece is?

Buggy was in Roger’s crew during his final voyage. This means Buggy has already been to Raftel, and he already knows what the One Piece is. Thats why he’s searching for captain John’s treasure instead of the One Piece, because he knows the One Piece isn’t treasure.

Who knows where is One Piece?

Only Gol D. Roger and Rayleigh are the ones who know about the One Piece.