As Ahmed bhae mentioned already, id like to add, A car cannot be imported with out an export certificate, Dealers how ever hide the orignal make photo copies to hide the mileage on it.
Secondly in Pakistan you cannot register the car without the export certificate or else the car is stolen/Smuggled, When you recive the return file from the excise office, Export certificate is attached in the file.
An export certificate maybe made before the auction and the mileage on the auction sheet maybe higher then that on the export certificate.
Export certificate is also registration cancelation as ahmed bhae mentioned, So it has to be made before the auction, Once the car is auctioned its directly transported (towed) to the ship yard and made ready for shipment no work can be done, All denting/painting jugaars are either done in Dubai or after they have reached Pakistan.
Thats why always avoid cars that come via Dubai.
My uncle just purchase the MAZDA truck, And he told us while inspection he saw welding marks, On questioning the dealer replied, "is mein dubai se water tanker lagta hai, So it can be imported under agricultural scheme, Yahan akei nikal jata hai."
So bohat 2numberi hai mere dost, If you can bear some tension finding a fantabulous car or have some jaan pehchan in karachi, get someone to find a car that is yet to be cleared from the port, Get it delivered from the port in front of your eyes, get it transported to your city. Such cars are always a bit expencive but peace of mind.
Or if you know someone whos directly importing cars to your city and has some parked at the dry port thats even better.