Question about content

Hey, I just have a simple question. I own a TGE license and was just curious about the rights to using any of the stuff that comes with the demos. For example, am I free to use anything and everything that comes with TGE by default?

Can I use any and all of the textures / models / skyboxes / weapons, etc? The EULA only seems to mention the engine and nothing about the demo stuff.

Basically, the reason why I ask is because I am a programmer and any and all resources I can use as a starting point to save myself time would be great!

Thanks,

-Greg