I placed my code for iAd/AdMob ads in...
Apple doesn't gets that specific when deciding to Accept or Reject your app. It only follows the guidelines, which doesn't get that much into the weeds of your specific methods.
[super viewWillAppear:YES] is a best practice, and I would recommend it. Always including super ensures that any code in the super classes get called before executing any additional code. So if you or someone else coded a super class that expected some code to be executed, you are guaranteed to still execute it, rather than just overwriting the whole method in the subclass.
Say you have a view controller of type
MyViewController which is a subclass of
UIViewController. Then say you have another view controller of type
MyOtherViewController, which is a subclass of
MyViewController. Say you're coding now some things in
MyOtherViewController. If you call super first, it will call
MyViewController before executing any code. If
MyViewController calls super first, then it will call
UIViewController before executing any code.