It is obvious that the ink has faded on the Australian one after 40 odd years and was written with a fountain pen, but the Obama one looks pristine and written with a ballpoint pen, which was considered déclassé in 1964. No Civil Servant of Britain or the ex Colonies at that time would consider signing an official document with a ballpoint pen. They would not even let you take examinations using a ballpoint pen.
Of course the typewritten font was more genuine on the Australian one for that era too.
Just taking a glance at the original it seems to me that it is printed in 8 1/2" by 11" paper, Standard American stock whereas European standard stock is A4, 210 x 297mm a little longer and a little narrower. So I doubt if this is a copy of the actual printed form from Kenya.
The Australian raised seal is off center, readable and initialed which would be normal for a hand stamped document. The other seal on the Obama document is perfectly centered, unreadable and not initialed which would be more likely on a fake.