'The Messenger of Allah ﷺ did not prostrate that day either before the salam or after."  

أَنَّهُ قَالَ لَمْ يَسْجُدْ رَسُولُ اللَّهِ ﷺ يَوْمَئِذٍ قَبْلَ السَّلاَمِ وَلاَ بَعْدَهُ  

The Messenger of Allah ﷺ prostrated twice after the salam on the day of Dhul-Yadain.  

أَنَّ رَسُولَ اللَّهِ ﷺ سَجَدَ يَوْمَ ذِي الْيَدَيْنِ سَجْدَتَيْنِ بَعْدَ السَّلاَمِ  

A similar report was narrated from Abu Hurairah from the Messenger of Allah ﷺ.  

عَنْ رَسُولِ اللَّهِ ﷺ بِمِثْلِهِ  

The Prophet ﷺ prostrated after the salam when he was not sure.  

أَنَّ النَّبِيَّ ﷺ سَجَدَ فِي وَهْمِهِ بَعْدَ التَّسْلِيمِ  

The Prophet ﷺ led them in prayer and forgot (how many rak'ahs he had prayed), then he prostrated twice, then he said the salam.  

أَنَّ النَّبِيَّ ﷺ صَلَّى بِهِمْ فَسَهَا فَسَجَدَ سَجْدَتَيْنِ ثُمَّ سَلَّمَ  

"The Messenger of Allah ﷺ said the salam after three rak'ahs of 'Asr, then he entered his house. A man called Al-Khibaq stood up and said: 'Has the prayer been shortened, O Messenger of Allah?' He came out angry, dragging his upper garment and said: 'Is he speaking the truth?' They said: 'Yes.' So he stood and prayed that rak'ah, then he said the salam, then prostrated twice, then he said the salam (again)."  

سَلَّمَ رَسُولُ اللَّهِ ﷺ فِي ثَلاَثِ رَكَعَاتٍ مِنَ الْعَصْرِ فَدَخَلَ مَنْزِلَهُ فَقَامَ إِلَيْهِ رَجُلٌ يُقَالُ لَهُ الْخِرْبَاقُ فَقَالَ يَعْنِي نَقَصَتِ الصَّلاَةُ يَا رَسُولَ اللَّهِ فَخَرَجَ مُغْضَبًا يَجُرُّ رِدَاءَهُ فَقَالَ أَصَدَقَ قَالُوا نَعَمْ فَقَامَ فَصَلَّى تِلْكَ الرَّكْعَةَ ثُمَّ سَلَّمَ ثُمَّ سَجَدَ سَجْدَتَيْهَا ثُمَّ سَلَّمَ