I do not. It's all speculation from a great many people at this point. The guy seemed to have the funds to do whatever he wanted from the sounds of it. Dude got a pilot license, owned planes, land, ect. He could have amassed quite an arsenal over several years/decades. If he had a pilot's license, to me it sounds like a guy that commits to things, so I would not put it past him to have went through all that ATF paperwork in order to lawfully own automatic weapons. I would not doubt if all the rifles were legally purchased full autos. But I also feel that if they were, the government has restrictions and tracks those purchases very closely. If he was up to something, he would be the first one to pop up on a government rader, especially now hearing ISIS is claiming this?!! I doubt it. But still an interesting twist if true.
Anyways you have as much knowledge on this as I do. All of us are speculating based on what we think we see, here, and our own experiences. Which is not much for most of us. I have fired guns, been around them but it does not make me an expert. I have extensively researched these bump fire mods as well as different AR platforms. I decided it was a rabbit hole I did not want to go down right now. But like others are saying, it sounds like bump fire based on the sounds but who can really tell unless you are around that shit constantly. And even then it does not make you an expert.