Originally Posted by Happenstance

Looks like during the first sync it "Join"s your contacts with your Facebook friends. If it misses any or you add someone new you can Join them manually from the Facebook contact. Menu > edit > Menu > Join [edit - you can also find separate the same way - if any contacts get inappropriately joined]

Also from the main contacts Menu you can toggle friends with no phone numbers on and off.

K, back to it - enjoy