The Premium Phantom differs from the regular Phantom in that it has at least two stripes connected which provides more white on the body compared to the regular grade Phantom. Juvenile phantoms will usually have some brown on them which typically turns solid black once they reach a size of 1.25″-1.5″.
As with most black clownfish, the black develops fully as the fish ages and matures. Early on it can have some orange mixed in. This will go away in time.