Cars get added to the registration stats when they are first time registered in Norway. This means that if you buy a Tesla in March and it is registered in May, the registration will be in May. If you buy a car abroad and import it to Norway, it will also be registered as this is the first time this car is registered in Norway. Cars cannot be registered twice and cars cannot be registered without an owner. The car has to be registered and must have insurance to get plates (registered).