The recent '50 0lds release has a choice of three builds- stock, Panam race, or Buck Baker NASCAR. It includes the roll bar for the NASCAR version and the partition between trunk and cabin (for when rear seats are removed). You should be aware, however, it only has the stock exhaust, so anyone wanting to build the race car versions will need to fabricate straight pipes. Not a big thing, though.
I love the kit so far. Lots and lots of detail parts, good fit, crisp molding. I am building the Buck Baker car.