Are you talking about an individual regional club's breeders list? That is different than being a member of a regional club. NCA has a set of guidlines or qualifications to be listed on the NCA breeders list, that many regional clubs do not require. You can view the breeder qualifications here:
http://www.ncanewfs.org/breeder.shtml Could be that one breeder has not met the requirements as yet, or does meet requirements and chooses not to apply. Also, if you are seeing some on the NCA list and not with their regional club, could be a couple of reasons. Many regional clubs do not maintain a breeders list for their club. If the regional club does maintain a list of club breeders, a breeder on the NCA list may chose not to list with their regional club by choice. Although that does not necessarily mean that the breeder is not a member of their regional club.