Uh, this is stupid. No one is gonna pay 3.5k for Unreal Engine. Besides, you have NO idea if this works. No proof = you're full of shit.
Legion told me they use 3D Studio Max and an export/convert plugin for the models, and probably for the maps too. If someone could decrypt the maps and model and recreate the plugin, we'd be set. He's actually WORKED with this stuff and had a lot of experience working with the ELUs and Gunz BSPs. I trust him more than some random guy saying it's written with Unreal Engine.
In short, if you provide no proof, none of us have any reason to believe it uses Unreal Engine to begin with.