Yes, but prior to that they used getdropbox.com, not dropbox.net (or something of that ilk). I do believe they were able to lawyer a squatter into releasing the dropbox.com domain after they were proven successful.
What are the legal grounds for "lawyering" him into releasing the domain?
http://www.techcrunch.com/2009/10/13/dropbox-acquires-the-do...