Well, as I pointed out in the article, in fact, the hands themselves are coordinated. With such a control system I think they don't have lefties and righties. Besides their Central brain doesn't have the left and right hemispheres.
But, it is possible that more of the octopus prefer to use the anterior and lateral arms, because they are directly in his field of vision, while the hind arms perform function of mounting.
RE: Octopus: The Cursed Genius of The Ocean