What would Kenya call itself in the interim, in anticipation, before they officially became the Republic?
According to Wikipedia, Kenya was made a Crown Colony of Great Britain in 1920 and remained in this status until its independence on December 12, 1963. Before 1920, Kenya was within the British East Africa Protectorate. It states that the republic was established a year after the 1963 independence and I infer from this that the Republic of Kenya formally dates from 1964.
Unless I overlooked it, I did not see the exact answer to Red Steel's question on what Kenya was formally or informally known as during the ca. 1 year between independence and the Republic of Kenya being formalized. http://en.wikipedia.org/wiki/History_of_Kenya
http://en.wikipedia.org/wiki/Kenya