Musannaf Ibn Abi Shayba 3:2127

Abu Bakr narrated to us, he said: Hafs narrated to us, from Ash'ath, from 'Ata', who said: Ibn al-Zubayr prayed, then he performed the taslim after two rak'ahs. Then he stood up towards the Black Stone and touched it, so the people glorified Allah (said SubhanAllah) at him. He returned and completed [the prayer], and prostrated two prostrations. He said: So I mentioned that to Ibn Abbas, and he said: "May Allah favor his father! He did not deviate from the Sunnah of his Prophet."