Base document Plot no Rectification after 4 registrations

Hi one of my friend wants to purchase one plot. 5 members registrations before the document mentioned wrong plot number but schedule property mentioned correctly. After that replotting done by referring old plot number. With new plot number, 5 hands changed without rectification of old document. Is there any issue, if we procure. Is it possible to get rectified now. Pls help me the way forward