NO DEMAND certificate & NOC for local registration ( it could be in one single letter ) from customs i.e mentioning that car WAS imported under diplomatic cover on ( date of import with engine & chassis number ) and after ( date ) there is no demand of payment of customs duty & import taxes, car is allowed for registration within x number of days ( 90 days ) by the buyer NTN no xxxxxx , CNIC xxxxx.
rest of the papers you mentioned are good as proof of purchase but not for registration - return CC plates when taking delivery - unlawful possession of CC / CD plates is crime and owners can lodge an FIR and may inform local police & foreign office of missing plate. exercise caution,