Well Alderran didn't really make an appearance in Sith war, It was just mentioned as the Qel-Droma Homeworld. Also Yavin 4 had been consumed by a firestorm at the end and finially Corellia might not have been put in place by that point. (meaning that they were moved at some indeterminate point in the past before the books movies but 4000 years is a long time so...