I was told about a 68 GSS. 440 dart and contacted a friend that worked with Mr. Norm and so he called to ask how to tell if it was a real Mr. Norm car.
From Norm himself, due to the fire there is no way to tell for sure, look at the age of the decal, sticker and the GSS emblem to see if it looks old or like a repop
So good luck on info you are looking for.