Was Kenya a British Colony?
AFAIK, only citizens of Commonwealth Realm countries (e.g., Canada, Australia, etc.), not colonies, can be knighted and be called "Sir". So Barky probably loses out there.
Now, that's not to say that the idiot media in the USA won't ignore this little detail and refer to him as "Sir Barack" - you can goldamnguarantee it'll be the case when he comes to cross his legs lady-style on "The View"