Well aren't we all actors to some point?
I'm thinking the models are honest to a point, but it is part of their job to create an illusion. Face it, first time sex between people that don't know each other well can be clumsy and less than stellar. And it is the crew's job to polish that illusion.
I would guess that most of what we see is real, but edited and punched up a bit. Tyler already knew what was going on when he showed up in that jeep with Aiden. Nu had already signed disclaimers before David found him surfing at the beach. Dakota and Jacob may not have actually worked at 'Homo Depot.' And none of the boys really thought that they were supposed to be with a girl before David pulled a switcheroo. I am 90% sure that David would be removing chunks of his camera from his scalp if he was really as spontaneous as potrayed.
It is like going to Disney; you pay your money, you have a great time but you know that the crocodiles in the Jungle Boat cruise are not really going to eat you. Although last time I went, i would have loved to eat the tour guide!