let me make this clear...
they don't just have, say 5 different necks ever made. All necks are different, it depends on what country they are made in, what factory they are made in, who was using the machine, what time of day it was (lol), what wood was used, what Tree it came from, how bright the moon was, what year it was.
they have so many factors you can Never pin down necks (this goes for all guitars).
