That is a myth unfortunately. One cannot date these cameras in this manner with any certainty.
The first Nikon F was produced in 1959 with serial number starting at 6400001.
By coincidence, the later annual runs were around 100.000 cameras, which made the two first digits "roll over" about once a year. However, during the first 5-6 years of production, the Nikon F sold in smaller numbers. Not sure about the F2 though. I have cameras with different serial numbers purchased more or less at the same time.