With the Saab is something not correct/legal.
It's regulary impossible, that worn out, damaged or abandoned Danish cars still have their license-plates. The Danish rules are extremely strict. If a car shall be brought out of registration, the plates must be brought to the police and will be destroyed there. So there is no legal way to keep non-valid license-plate at home or in a collection. When the original owners had lost their car by a crash, later on they had to do everything possible to get the plates and bring them back to the Danish police.