Honestly, it really does. Nothing about that suggests they are making up anything. It's throughly organic; off the top of their heads. None of the body language or vocalization suggests deception to me. They include esoteric details and caveats without hesitation. It's fun to watch, thanks for posting.
Does this sound like a group of guys who just accomplished the most impressive feat of human innovation?
https://www.youtube.com/watch?v=XeAGGpRYmKY