Re: Correct Number of Sunnat Rakats
Aishah (May Allah be pleased with her) reported: The Prophet (PBUH) never omitted four Rakah prayer before the Zuhr prayer and two Rakah prayers before dawn (Fajr) prayer.
[Al-Bukhari].
I found this one while searching. This is about fajr and zuhr prayer
So I think ur question about zuhr is answered.