Beware! you working on the assumption that "the lady" knowns what she is talking about. It is rare that any in-store assistant can differentiate one castrol 5W40 from the next.
I don't think that the bar code will change based on the country of origin. As far as most parts stores are concerned, Castrol 5W40 is Castrol 5W40. I know that the bar codes are the same for Green and Gold GC.