It is Dark Shadow Gray to confirm above. It is a common color used on Expeditions, Escapes, F-Series Trucks, and the Villager applied as a basecoat clearcoat. Not sure if it was available on Mustangs in '03 as I don't have the books beyond '02 handy.
Thanks guys. I recently purchased the original brochure from SVT for my 03 Cobra and it says nothing about Dark Shadow Grey as an option. I thought that is what I had untill I say the brochure. I will now change my sig back the way it was.