My Father had purchased a Flat in the year 1986. Agreement was prepared in the Year 1986 on 5 Rs Stamp paper. We intend to become a member in society but society says that payment of Stamp duty is compulsory but as far as my knowledge is concern i am sure that stamp duty is not payable as the flat was already purchased by means of agreement in 1986 and only registration for the same is to be made.
Please guide whether stamp duty is payable or not and how to register the same as both the purchaser and seller are deceased.