How to understand a narration that says Holy, King of All Prophets Holy Muhammad (Sallallahu'alaihiwassalam) believed in the Torah?

The following Hadith has often been cited by many people to prove that the Jewish Torah has not been corrupted:- He (the Prophet, sallallaahu ‘alayhi wa sallam) was given the Torah and he took away the pillow from beneath him and then he put the Torah on it and then he said: “I believe in you [Torah] and in the One Who had sent you down.” (Sunan Abi Dawud 4449) Many people believe that since Prophet Muhammad (Sallallahu'alayhiwassalam) said, "I believed in thee and in Him Who revealed thee", this proves that the Torah that was in front of him was not corrupted. This is something contrary to the Muslim claim that the Torah in its present form has been corrupted. **Question: What is the truth behind this narration? Is this narration even authentic? It has been cited in Ibn Kathir's Abridged version of commentary.**