Sweden needs help! 300GD 1983 ! with certificates

Hello! I have a 300GD 1983 and having trouble with Swedish autotest (tuv?) The car was taken to sweden 1987 and in registration the write “Truck” its Beacuse its lower tax on truck ́s But its not allowed to have passangers. so the rearseat was removed, but its back in place now an i want to register it as a family car so i can use the rear seats. But neithers autotest needs to know that it has been made to be a car with rearseats when it was first put to traffic… and in what country! Looks to me like its impossible?! ? I need to know where my car was sold and in what country is was taken in traffic for first time.