it may or may not be, how are we supposed to know? It looks a little high, try putting a multimeter to the battery and see what that says. Then try 5 more multimeters and see how consistent they can be.
Looks about right. 12v batteries sit somewhere between 12.8-13.2 volts, and your alt should run around 14.4v. If it's going up to 15v or more then you might have a problem.