The earlier 104s also have the two fan set-up, but I think the Cs fans and low speed have been modified a bit as they are different part #s than the 124/104.
Prob a little faster low speed, as they also changed the resistor part #. That would indicate a speed change..
That would account for the large difference in temp specs between the high and low cut-in of the ECT specs and why you hardley ever see a high fan.

As you say, the fan management is the biggie and one will notice that even later models have finally dumped the viscous for an electric puller...Think that was way over-due....