Back when many of the companies were getting started, all pickups were wound by hand. This does not mean they were wrapped by hand, but the wire was guided by hand as the pickup bobbin was spun on some type of device.
Fender used to hand wound the pickups until 1965, then CBS bought this company and change to a complete machine wound method. This method change caused the birth of the legend of pre-CBS Fenders, which has continued to the present day.
Gibson also used to hand wound the pickups, in the 1965-1968 period starts to introduce machine wound, and from 1969 to the present day this method was the only used at the Gibson factory. The hand wound method of winding of 50’s Gibson pickups, has a great influence on the sound of these guitars, and is one of the reasons of the high price that these models have today.
Why hand wound is better than machine wound?
Machine wound pickups have the same pattern of wire layer by layer, while hand wound pickups have a random pattern in every layer. This increase the structural richness of the pickup that have a strong relation with the sound produced. Because it hand wound pickups are more colourful, lively, and have a richer tone. This is the reason why more expensive custom shop editions have hand wound pickups.