The property is identified by various markers such as Khasra numbers which help to identify the property.
You may register any document tht you wish to register by paying proper fees and if it is to be stamped like in all documents relate to property then the regostrar will check if proper stamp duty is paid. They will not look into other matters. So you may have registered documents without the khasra numbers sometimes but these documents are not helpful in claiming ownership of the property as proper identification cannot be done.
So it is advised that you do not deal if the khasra numbers are not there.
S Jadhav