Admittingly I am resistant to the whole "non-symmetrical" idea...I can see how it would make sense from one point of view, considering the opinion that Borg cubes are grown, not constructed, but this is really fanon. There is nothing to say, even if the cube is grown, that the plates could not grow to be symmetrical. I would think that both are possible. I might play with the idea later, but for now I will keep them symmetrical.
One note though...all the plates are different, and there are even corner caps, so anyone can bash it to give it different plates on each side.