On my 9700 with the latest Facebook app, you could go to the friends list and see who had their BBM PIN connected to Facebook, as there was the BB icon by their name.
Now, that seems to have gone away. Now, if you go into your contacts you can see your Facebook friends in your contacts and you can Invite them to BBM, however, I believe it is using their email address for their BB ID instead of whether they have their PIN set up on their Facebook account. If they use a different email than the one they used for their BB ID or if they don't have an email address tied to their Facebook account, you can't tell if they have a BlackBerry or not. So, even if they have their PIN on their Facebook account, it won't give you the option to add them to BBM unless they have their BB ID email address on their Facebook account.
This is good in one way because you can now tell if they have a PlayBook as well, but negates the fact that most people still have their PIN tied to Facebook only. I'm hoping as more people move towards the new Facebook app that this will become a moot point.
Now, that seems to have gone away. Now, if you go into your contacts you can see your Facebook friends in your contacts and you can Invite them to BBM, however, I believe it is using their email address for their BB ID instead of whether they have their PIN set up on their Facebook account. If they use a different email than the one they used for their BB ID or if they don't have an email address tied to their Facebook account, you can't tell if they have a BlackBerry or not. So, even if they have their PIN on their Facebook account, it won't give you the option to add them to BBM unless they have their BB ID email address on their Facebook account.
This is good in one way because you can now tell if they have a PlayBook as well, but negates the fact that most people still have their PIN tied to Facebook only. I'm hoping as more people move towards the new Facebook app that this will become a moot point.