Sales deed unregistered

Hi all, We are living in a house which was bought in 1979, we have sale deed but its not registered, it was written on my mom's name but our mom is not alive now. we are two brothers and father living now. My father wants to partition the house and register it on my and my bothers name. I'm planning to take house loan but bank people asking for registered sale deed which we don't have(just have sale deed on stamp paper) and we don't want to have any breakup in our link documents so please suggest what we can do to avoid the link break in our documents. We have talked to brokers who do all property registration they are saying make a gift deed which in turn can be registered on our doing this once the property is registered on our name will we have any issues in future while just holding registry papers and gift deed papers ? Remember we don't have any clue where the people are who sold us this property. I would be thankful if you suggest me if we can just register property and willn't have any issues in future. Thank you