~”Did God speak through Joseph Smith when he proclaimed that God the Father was not always God and that he once walked upon another world as a man before he BECAME God?”~
Yes, I believe so. That is LDS doctrine, and is consistent with our belief in the deification of man.
Funny Gordon Hinkley denied that the LDS Church taught that doctrine.
Was God speaking through Gordon Hinkley when Gordon Hinkley essentially denied that the Mormons teach that doctrine?
Here is the relevant excerpt from President Hinckley's interview with Time:
Q: Just another related question that comes up is the statements in the King Follett discourse by the Prophet.
Hinckley: Yeah
Q: ... about that, God the Father was once a man as we were. This is something that Christian writers are always addressing. Is this the teaching of the church today, that God the Father was once a man like we are?
Hinckley: I don't know that we teach it. I don't know that we emphasize it. I haven't heard it discussed for a long time in public discourse. I don't know. I don't know all the circumstances under which that statement was made. I understand the philosophical background behind it. But I don't know a lot about it and I don't know that others know a lot about it. [emphasis added]