If you're using CloudSQL, django models are supported, and you'll be fine.
If you're using the HRD, getting the admin pages to work would be more difficult.
django models are not supported. The app engine SDK comes with django-style forms that work with the GAE db.Model fields.
Alternatively, you can use django-nonrel which includes a translation layer that allows django models to be used with GAE. The translation layer has various limitations, most prominently, many-to-many relations aren't support. This breaks the Django permissions module which is used by the admin. I've seen some attempts documented to get around this, but I'm not sure how successful people have been.