Yes, unless they're the stickerless ones (the one's with colored plastic instead of stickers).Thanks guy,
and side question.
Are Dayan Guhongs allowed in competitions?
(or the plastic comes in white and they have to dye it black for black cubes)
Nope. white the white plastic Lingyun 2 is noticeably different from the black version.
Ah yes, I was looking for something like this instead of just one white cube is better than one black cube. Seems weird though, I can't think of anything that would make white better.