That would make much more sense, as a WASR is fairly described as an AK. The reporting from the link you provided cites back to the police as the source, but this is also the same police that gave prior confusing statements about an SKS/AK rifle, so it's probably best just to wait for better info.
A betting man would guess that the WASR ends up being the weapon used. There was a time when SKS rifles were dirt cheap, but nowadays cheap AK imports are only a few hundred more than a cheap SKS rifles, and the AK are more modern. I would imagine someone going on a suicide mission probably isn't worried about blowing up their credit card. Both are equally easy and legal to acquire in Nevada.