GY9 is Dark Gold Metallic for Dodge and Tawny Gold Metallic for Plymouth.
Extremely hard color to find referrence for with what you want. But i am pretty sure the picture of the Challenger has the Gold vinyl roof, it is a dark color similar to what is the color of the car.
The 'Cuda pictured has a white vinyl top.
You should see if you have a sample piece still on your car under one of the stainless trim bits any where from front to back, fingers crossed. This will help distinguish the correct coloring.