The factory stripe is what is shown on that "classic" in my picture.
The '70 style is a thin stripe that runs right along the bottom of the beltline and goes from front to back, with an "R/T" on the fender where the "Challenger" emblem is on the "classic". It is also known as the "longitudinal" stripe.
There is an aftermarket version of that stripe available for new Challengers, I've seen pictures of a few cars with it installed. I think the '71 style stripe looks better though!