I doubt they are that light. I have a 65 mustang (smaller than a 68) with aluminum heads, radiator, manifold, center section, lightweight coilover front suspension (my design), carbon fiber hood and a lot of other parts that are lighter. My car weighs 2800. My 65 falcon weighs 2699, it has a fiberglass front end, a lot of aluminum, lighter front seats, lightweight coilover front suspension (another one of my designs).
i would guess closer to 3200lbs. They added a lot of steel and the car is wider.