Cheekie, not all RWD cars have staggered rear wheels, or deeper lip on the rear wheel, which is what I'm guessing you refer to when you say the rear wheels do not look like RWD. It is a popular look now, so popular that even some FWD cars are finding ways to recreate it, so wheel appearance cannot be used as a reliable indicator of drivetrain layout.

With regard to AWD: AWD adds weight, which is the last thing the Challenger needs. I don't think it's impossible that they would add it later, given that some of it's LX platform cousins are using AWD, but I'd probably opt for RWD and either run snow tires in winter, or keep it out of the snow entirely. A classic style American muscle car that couldn't do a rear-wheel burnout would freak me out