BH,
"My son reminded me that the fan was turning when we tried to crank it."
If you have an original style fan/belt, it turns when the engine turns; and, the engine turns when it is cranking on start-up.
Do you mean that the fan was turning before you cranked the starter/engine?
They key was in the on position, and when I stepped on the floor starter, the fan began to turn. Am I answering your question? I believe it's all original as far as fan/belt is concerned.
BH