IMO the expanded black areas are an indicator that it is a True Perc. However its not a 100% way to guarantee that it is, the only real way that I have read is to count the spines on its dorsal. 10 or 11, one is ocellaris the other is perc, but I dont remember which is which. And then there is the perc ocellaris hybrid theory, IMO completly possible. Cool looking fish though.