I have to agree with Lycanthromancer.
Plus, if you follow it logically, you have gained the bonus from years of experience. If that knowledge doesn't go away, then neither should the bonus. And the stats given in the various bestiaries are the basic stats for the creature, and any of them can be changed or enhanced per the monster improvement rules. So, in theory, anything can be improved.
Besides, if he's PaO-ing into a Sarruhk, anything else is irrelevant details. Because then he just needs a friend to PaO into a scaled one.