The problem here, though, can easily be solved by just choosing which sourcebook and era you're using: the Folio, the Boxed Set, From the Ashes, The Adventure Begins, or the Living Greyhawk Gazateer. If you're using the LGG, go by that and ignore everything else. If you're using the boxed set, go by that and ignore everything else. The thing with tiny inconsistentcies like this is that they are so easy to resolve—just choose one and move on with it. No creativity or effort required.
Greyhawk, after all, was originally designed as a bare skeleton for the DM to dress up and make their own (unlike the Forgotten Realms which will tell you Elminster's favorite tea or who the Mullhorondi's favorite top pop stars are). If you want something not in the setting books to happen (like including warforged), make it happen (say that they were created by the Shield Lands to bolster their forces to combat the legions of Iuz). Certainly don't sweat the small stuff like the levels or name of a country's ruler (especially when you can just choose which source you're considering authoratative).