Property not registered can it be counted for property tax payment

Property Paper has been named on two brothers around 30 yrs back.And these brothers are had a Fight in between them back 20 yrs ,and then they decide to leave separately in same property like for example one brother will stay in left side and the other one on right side of the property. they had not done this thing in written and they just discussed this in words. 5 yrs back one brother builds 3 floors on his side and now whole property is to be divided, so how whole property should be divided? So I want to ask that does that 3 floors built on one side should also be divided equally between two brothers or it goes with the on who built it? Note:-Those 3 Floors is not yet registered in Mahanagar Palika. -And property tax is only on previous state of home,it is not on those new 3 floors built on one side, so it does not comes under property tax because it is not yet registered.