There wouldn't be. There is a Dub edition with the Roush body kit parts. There isn't a Roush Dub Mustang manufactured through Roush.
EDIT: I stand corrected. Reading a little about it I misunderstood. Sounds like it is partially assembled at the Roush plant. I wonder if the Dub editions have a serial number? Maybe if they don't that's why they don't show up on the production list.