Self Acquired/Ancestral Property Rights?

The property was self acquired by my Great Grand Father who died intestate. A partition deed was executed in the year 1979 where in the parties were my grand father his 2 brothers and their mother which made equal parts of 1/4. Now as the partition took place, the ancestral property became self acquired of the 4 members mentioned above. My father ( now passed away) was born before my great grand father died intestate, shouldn’t he be the 5th member to get the share in the property? If yes, do I as his son and great grand son have a right to challenge the partition now, as it is jeopardizing my interest. Also, My grand father (passed away in 2006) made a will of his aforesaid acquired share and though I’m mentioned as a beneficiary in the will. My grandfather has made my grandmother the absolute owner of the property and she is biased towards her daughters and not inclined to give anything to me or my widow mother. - Do I have any right in the property? can I challenge it?