My Street car was painted by Connecticut Custom Car. They painstakingly tried to find the correct Guardsman Blue, which there can be some different varieties. I think they came up with this color as being a very common one used by Shelby.
I'll post some pics of the rear of the car since there is so much paint in the rear and a lot of different angles....you can really see how the light hits it. If you like the color, I'm sure you could purchase the paint from them.