Hello im new to forums so sorry if posted in wrong place or in wrong format

Ive bought a cd500 navi and phone kit to retro fit to my 10 plate insignia neither unit has been divorced and i havnt got the car pass for the car the units were taken if i buy peckys decoder can i get the code from the reg or vin or do i need to read the eeprom of the units if so how do i go about it and what programmer/reader do i need thanks in advance