Sale of flat in a property developed under 33/7

Dear Experts, Ours was a Chawl system in Mumbai which was developed by private developer under rule 33/7. and allotted flats in new building along with allotment letters in July 2014. our society is proposed, and we are waiting for builder to register it. can I sale such flat?? if yes then will it get transferred to the buyers name immediately?? do they accept it for registration at sub-registrar's office?? who will give NOC I have heared that there is ban on sale of such flat for 5/10 years? is it true??