If noc reqd even if there is reg will

no since the property is willed to him by his father he need not get noc from anyone and can mutate it on his name

What do you mean by transfer of property, is it transfer to his own or transfer by sale to a third party?  In which place are you? In India in some places particularly in metropolitan cities a Will needs to be probated. When the will is being probated, the Magistrate may give public notice asking for objections, if any. If no valid objections are received the probate will be granted. Granting probate means issuing authenticating document in the name of the successor or successors. In some States there is stamp duty for the issue of probate. In places where no probate is required there is no formal transfer document. The question of ownership will come only when one wants to transfer the property by sale or otherwise. The purchaser may insist on the authenticity of ownership to protect himself from counter claims.

i agree with dr ramani.suppose if the property is located within the jurisdictional limits of high court of metropolitan cties - chennai, mumbai and kolkata then the probate of will is compulsory. in all other places its optional-only when legal issues are there