Its difficult to protect the models for those who are distributing games or demos for others to download unnless you will distribute all content embedded as one .exe or you want to get into some kind of argument with those who may wish to use them in their own creations and I am sure there will be some who will.
I presume the models may eventually be available to all anyway as an add on model pack so they wont be kinda exclusive.
The only way to really have exclusive is too make absolutely all your media yourself and thats a big job for us small developers.