The M-16 look alikes probably were M-16s, but they could have been 9mm submachine guns as well.
Notice too that the BATFers (Now BATFErs) are not taking cover, only concealment. Those horse trailers weren't going to be giving any protection against an M-60 or a .50 cal. In fact that was the first time I heard or read anything about a Machine Gun, (as opposed to an illegally constructed assault rifle) and I've read quite a lot on the subject. There was never any evidence submitted, as opposed to agent testimony, about any converted converted assault rifles either, AFAIK, nor were any outside experts, such as NRA experts, allowed to examine the alleged converted assault rifles, to see if they had indeed been converted, and if it was done before or after the fire.
They also never mentioned the large hole blown, somehow, in the roof of the central concrete block area of the building. I saw photos of that hole. The re-bar was bent, and the concrete was pulverized. Of the evidence was promptly bulldozed, and unusual procedure at a crime scene.
They did show the explosion that might have made the hole, and it might not, as that big explosion looked more like a propane tank or other fuel tank going up.
They mentioned that the investigators (From the BATF itself IIRC) found accellerants, never mentioning that the FBI had knocked over the fuel tank with either a Bradley or the CEV (modified M-60). Speaking of tanks, they repeated the misinformation that the "Army" provided M-1 Abrams tanks. They did not, the Texas National Guard provided Bradley fighting vehicles and the CEV.
All in all, the program was a apologist POS.
Let us also not forget the JBTs shot some of the Davidian dogs before going to the front door.
Let us also not forget that the front door and its bullet holes disappeared. No one can determine whether the holes point in or out.
Let us also not forget that the refrigerator containing the Davidian dead bodies stopped working.