It depends on the model/value of the car, as for an old car like Mehran 96 it would be sold 40-50 thousand less than market value and for a newer/expensive car like City 2005 it will be around 1 Lac.
If U find the original later it would have to be inserted in the Duplicate File.
Another thing is that U can only get Duplicate file procedure done if the car is registered in your name and U have your valid CNIC with U.
So if U r not getting it transferred in your name or selling the car in near future don't bother as it doesn't matter when U drive it on the road.