1. A Latest Mumbai High Court judgment states that the Last available "Registered Sale Deed" of an immovable property is Final & Conclusive and earlier title documents are not required, IF the property was duly transferred /mutated in name of Mother.  This registered document is legally Final, for all futuristic legal purposes such as Sale /Transfer /Gift /Donate /Mortgage /whatever....

2. Possession of such property for a period of more than 30 years, makes it time barred for any legal disputes, at the hands of other claimants.

The registered document on your mother's name itself is a title document.

However if you want to secure the title of the property more clearly then your mother can execute a registered settlement deed on your name or your sibling's name.

The tracing of title can be clearly mentioned in the subsequent registered document in the recitals so that there arises no doubt in the minds of anyone who may have to transact with the property in any manner in future.

Your mother does not have clear and marketable title to property 

2) your mother has possession of property 

3) you can seek to obtain loan on basis of registered document executed by your mother family members in her name 

4) your mother can execute gift deed in your and brother name 

Generally all original link documents for last 30 years are required for loan. 

Unless property not registered, property don't have a clear and marketable title .

you mother can execute gift deed. 

If all mutation papers are on your mother's name than it's clear title property. And you can go for loan against property.

Get property papers from tahsildar office for last 30 years. If it's on your mother's name than it's clear title property. 

Check with bank of your area which papers they require to pass loan against property.

Title of your mother is clear for the property transfered to her by her brother and mother through registered settlement deed. 

You can get loan on this property easily. 

Or you can ask your mother to transfer the property on both your names through registered gift deed. 

See if you have clear land possession  and panchyat khata on land the title is clear, also if the share of grand mother and her brother is also registered to her by registered deed there won't be any issue you can apply before the bank for the loan the bank can scrutinize the document and based on documents get legal search report from the bank lawyer.

Also re registration in your name also will not clear title if the back documents are not clear. 

Title is clear and abut missing link, if she gifts or bequeath property than she can mention those details.