Right in property

i need know abt son's right in father's property passed on by his father,

approx 30-35 years my grandfather have transfer in inherietance 01 each flats on my mother's name and father's name. there is no transfer agreement and it was done the share certificate by society committee. both flats were purchase by my grand father. do i have a clam or rights in this property. i have elder sister also. does she also have any right or clam on the said property