I'm going out on a limb here, but looking at the outside closeups it does look like it <should> pass muster as non-restricted. Notice the pin where the "auto sear" would be on a real AR. I'd hazard a guess that this thing is sear, rather than hammer fired. So what I see here is something that is likely to have a short "bolt" that doesn't require a buffer and tube, and a sping loaded firing pin, and thus would have a different trigger mechanism than a "real" AR, as such, that would make it a completely different design internally, hence non-restricted.