Are vintage Fender Stratocaster pickups all wound with the same number of turns?
All the early Fender single coil pickups were hand wound and used a rubber-band from the motor to the counter that also turned the bobbin. The counter was used as a guide for the desired number of turns. As the rubber-band got old or worn the counter numbers could vary. The rubber-bands could slip and inaccurate turns could be counted. The main thing that determined the number of turns that could be put on a bobbin was basically the specifications on the magnet wire being used and winding tension. The variance in tolerances could make the coil fatter or thinner and also the OD (outside diameter) of the magnet wire could vary and giving the pickups many variables. I ve seen coils wound quite full with low DC resistance and have seen thinner coils with higher DC resistance. The tension is very important too when hand winding and precise hand winding can make for a beautiful coil as seen on many older Fender pickups.
