In the world of casting interviews and auditions and issues of what actors may be better suited for certain types of characters, etc., why wouldn't it have been possible that the three-page "audition" script handed to Nichelle Nichols by studio execs had lines from the three characters that she says it did: Bones, Kirk and Spock... if she had seen something in those three pages that referred to a MR. Spock, then why would she have asked the execs to explain what "she" (Spock) was like?
Isn't it possible that they simply wanted her to read certain lines to see how she would handle specifically-written characters? I have no problem with that process, regardless of whether or not Nimoy had already been cast. They still could've simply wanted to see how she was as an actress.
I don't think Nichelle lied to me when she told me this story, or that she somehow mis-recalled the facts of her audition. I trust that it happened as she said it did, and she was subsequently given the part of the communications officer, whose name resulted from the book, "Uhuru," that she had brought with her to the audition. As far as I'm concerned, it's an interesting story, a good part of the overall "Star Trek" lore, and case closed.