Interesting question. Trying to put it in context: I assume Michael, rather than Tom, would have served as consigliere to Vito at the time of Genco's death. Answer: no. He had no organized crime experience and had rejected his family to that point. Even if he had made a sudden conversion to the family cause by the time of Genco's death, he'd have had a real problem with credibility among Tessio, Clemenza and the troops.

Real life instance: Joe Bonanno named his college-educated son, Salvatore (Bill) his consigliere without Bill having made his bones. That move was deeply resented in the Bonanno Family, and when Joe ran afoul of the Commission ca. 1963-64, about half his family defected, in no small part due to Bill being made consigliere.