The description says: "... the first 100 guests who register on our webstore before June 15th will receive even more..." but as far as I can tell, there is no way to know whether 100 people have already signed up or not.

If I only want to go if I also get the bonus stuff, it is a big gamble that I am not sure I am willing to take.

The store item should indicate whether what you are purchasing is a first 100 registration or not.

That is a very good question.  I know that my group bought our tickets the very first day when they came out.  We didn't want to take any risks with not being in the first 100.  I think it would be sad if we bought all of those tickets and not one of us made it up in the top 100.  I would think that you would still be good if yo bought the ticket from their website, but one never knows about these types of things.  I guess you just have to play the odds.

 I just got an email from Customer Service asking about the first 100 and they said they have spots still open so I will be signing up today!

They'll post on the website when they've hit 100.