last i checked from the point the syrup is mixed to the point it goes in the bottle, it stays in the same plant. At least that's what my friend emily says (harry you probably remember her from middle school). her dad is the office manager of the coke headquarters here in downtown Atlanta and the local bottling plant. the syrup definitely never leaves the facility like tht.
Remember, we're talking about coke here, a company who guards its formula with security that rivals that of swiss banks.