The rocks dont set up the territories per say but allow breaking line of sight to aid in limiting aggression and such. Though I dont rank this tank as bad per say. Not something I would do but way better then the guys with 2-3 oscars in a 55 gal tank or such.
Driftwood will lower the PH, add some rocks, slate, or clay pots, zillions of them at HD for a song, they also have colored ones if you like color in your tank.