We think that He was, but a lot of that information has been lost from the Bible. For example, the Book of Mormon mentions two OT prophets by the names of Zenos and Zenock who were very specific about Jesus Christ, but who are no longer found in the Bible. The Book of Moses contains many references pointing to how detailed a knowledge the ancients had, starting from Adam down, about Jesus and His future ministry on the earth. The Book of Mormon also has an account of a very remarkable vision that the Brother of Jared of Jesus, which would have taken not long after the Flood, and the fact that the Jaredites had considerable knowledge of Jesus and His ministry on earth. We think that a lot of this information has simply not survived in the Bible.
That is a valid observation, thank you.