I have moved this post from the Navisworks Board to Installation & Licensing, since this question is in regards to installing a service pack through a deployment.
I did find on the following blog posting that SP2 contains all of the fixes from SP1 (meaning you do not need to install SP1 prior to SP2):
http://beyonddesign.typepad.com/posts/navisworks-freedom/
Lance Coffey
Technical Support Specialist