Give it a rest Cyn, dig deeper yourself since thats all you are going to believe. Kenya became a Commonwealth in Dec of 1963. Look it up.
And a Republic in Dec of 1964, by way of a constitutional amendment, at which time Prime Minister Jomo Kenyatta became President Jomo Kenyatta. So, the document falls hard, unless it's shown the government offices jumped the gun with the letterhead by almost a year.