is it possible to crack open standalone for windows or mac

and get the FBX of the models? i want to protect additionally my work...any advice appreciated!

Any 3d model that will be eventually rendered by the GPU will never, ever be protected and can easily be ripped. This has nothing to do with Unity; you can rip 3d models from any AAA multi-million dollar budget game just as easily.

If someone can crack the PS3, then they can crack a standalone Unity executable. I can't comment on how hard it is, but I would expect people to be able to get at the assets if they wanted to.