Not really.
The Registration Domain is never written out to disk and its added at the end of the defaults search order so its only read if nothing else satisfies the search for a key value.
The idea is that you use this domain to provide default values that your app really needs to not crash at runtime. For optional things the UserDefaults methods return values that you can use if there isn't a value listed for the key.
The way I normally use registration is to have a plist of my default settings in my app bundle that I read in at launch. That way updating the basic defaults doesn't involve any code.