Is it true that it was authentically reported from Ibn Abbas that the Messenger of Allah, peace and blessings be upon him, used to perform the prostration of forgetfulness (sujud al-sahw), whether for an addition or a deficiency, at the end of his life before the salutation?

The attribution of the statement that all prostrations of forgetfulness (sujūd as-sahw) are after the salām to Ibn Abbas has not been verified. However, it is attributed to Al-Zuhri, whose view was refuted by Shaykh al-Islam Ibn Taymiyyah, who considered it an unsubstantiated claim of abrogation. The correct view is that some prostrations are before the salām and some are after, as established by authentic hadiths. Two sayings have been reported from Ibn Abbas on this issue: one stating that all prostrations are before the salām, and the other stating they are after it.