They did.
My first really succesful radiator setup in the '67 with the late style timing cover and water pump was a semi-custom square top and a factory flex fan with short spacer. Flex fan blade came off on a road trip but went right into the battery so the radiator survived. Fan shround did not.
Later I shifted the core and tanks further forward on the side mounts. This allowed just enough clearance to use the MP clutch fan.
A couple years ago Bob at Glen Ray made me a bubble top '68 radiator with the lower tnk from a '70. That's been working great, and lets me use a clutch with the correct earlier fans and '68-9 shroud. I think that's the best way to go...natureally. :)