Aye. But since the literal form of the riddle of steel holds true in One Piece, Oz can't possibly be brought down by mundane means any easier than having him eat the shitload of salt. Unless the others just keep him busy until Luffy beats Moria and thus sets all the shadows free.

It could be even interesting if the rest cooperated perfectly to have Oz ingest all of it. It would be almost the first time such cooperation happened...