Yes, I naturally assumed buses back then would have looked entirely different.

Long-haul trucks are another good example. A Peterbilt 359 from 1967 looks a lot like a Peterbilt 379 (aka live-action Optimus Prime) which was last produced in 2007.
Generally speaking, vehicles in which function is more important than form tend to be very conservative in changing their appearance. Farm tractors, dump trucks, train engines...it's often difficult to identify, without detailed knowledge, when a particular vehicle's design comes from.