@Smart Pig,
They don't seem to be consistent (I just checked).
If there is one, then it's on their account, just to the right of the 'add friend' button. This depends on their settings.
If you want people to follow you (just so you can see how this is done) go to Settings>Public Posts>Who Can Follow Me and select 'Public'. The only other selection is 'Friends'.
You can (I believe) friend them and then go to their profile, pull down where it says 'friends' (just above 'message') and pull down, selecting 'acquaintance'.
But again, the privacy settings are terrible. FB doesn't seem to realize people might want to segregate their friends (say, if you have a friend who's also in sales, and you don't want them to bug other people on your friends list - far as I can tell, that can't be done, which is silly. It's a perfectly valid use case).