Yeah Ron, I'm not sure either, but I too don't recall the pin-striping being on the Fastback tanks...though I think it looks good on it here.
And yeah, the bodywork is interchangeable. Good point. In fact, my buddy Phil with all the classic bikes in CA has a '75 Commando Interstate(larger tank) with the Fastback seat/tail section on it, and which he's told me the guys who have done that to their Commandos call their bikes an "Inter-Fast".
