I avoid the words 'real' & 'original', when I respond.
I usually refer them to the license plate or dash plaque, and tell them they are looking at an authentic or, genuine Shelby Cobra, CSX4795!
I ask them if they know that Carroll Shelby is back in the car business? Have they seen the new Shelby Mustangs? Well ol' Shelby has a factory down around Las Vegas and makes 'Shelby Mustangs' for Ford & 'Shelby Cobras'. This is one of the brand new Shelby Cobras.
I didn't spend all the addition $$ for the 'Shelby tax', and wait for 3 years for a CSX number, NOT to say that!
I paid dearly for my car to come with Cobra emblems 'already' attached to the hood & trunk!
I also enjoy saying: "Yes, it's a genuine 427 side oiler!", but that's for another post.
jdog
P.S. The next question is the one I won't answer: "How much?"