Dear Experts,
I would highly appreciate if you can satisfy my curiosity about following:
X (seller) and Y (purchaser) entered into agreement to sell and got duly registered on terms and conditions.
Later both agrees to add more clauses into agreement. If they specify such clauses on Rs100 stamp paper mentioning reference of previously registered agreement to sale and get it notarized (THEY ARE NOT REGISTERING IT), will it be equally respectable under eye of law if any dispute arises between seller and purchaser?