in the uk we can buy and sell car registrations and take a reg off one car and put it on another,theres a huge amount of do's and don'ts that go along with it though,i would think that the reg m548shh is nothing special,its the car that special.
people would love to buy say r1fmc or p10fmc due to what car they were originally on and because they look good on a nice ford car.
them kind of refistrations tend to stay on the original cars though due to the fact they make the car worth more.
i could not see anyone taking the reg m548shh off and putting it on another car unless the original car was badly damaged. lots of rally escort cosworths got badly damaged and broken for spares and its anyones guess what happend to them.