Unequal distribution of ancestral property

My grandfather has 3 sons and a daughter. His elder son is my dad. He distributed agriculture land unequally where my dad got 6 acres, 1st uncle got 11 acres, 2nd uncle got 6 acres and my aunt got 10acres. There was 4 acres of land on my grandfather's name which was gifted to my 1st uncle's son without our knowledge in 2015. My grandfather expired last month. Registration was done without passbooks and without our knowledge. We were cheated as we got the least share out of which 1 acre is under dispute with endowment department. Do we have a right to fight for equal distribution or can we fight for the land which was given away to my 1st uncle's son? My father sold 2 acres from the 6 acres given to us and my 2nd uncle sold 1 acre from his 6 acres. This property is my grandfather's father's.