Yes, the diodes are included as per the diagram. I get 4.2V at the fan even with one shaded array. The 3.3-5V (advertised) fan just won't start without encouragement. I used this same approach and the same diodes to add a second, southeasterly facing, solar cell to my Acurite 5-in1. That worked well.
Maybe I'll remove the diodes, try that, and then try wiring the panels all in series to throw 8+V at the poor fan. I'd hoped there might a capacitor solution that would kick-start this little induction motor.