The user guide and admin guide go over how to change the port assignments from static to dynamic (page 57 in the C90 Integrator's Guide). What's not in there is what's the default configuration. I'm guessing it's set to dynamic, but can't confirm that anywhere in the guide.
Default H.323 Port Allocation is Dynamic at least with recent release software version.
Just to add to what Tomonori said, you can always check the default configuration by saving your configuration and doing a factory reset. Whenever the codec is factory reset, it is restored to the default settings.
Regards,
Mubashshir Akhtar