Is this proof the rebels used sarin?

www.wnd.com... If this video is floating around on the net surely the powers that be have seen it?

The problem is, that this are propaganda videos of pro-assad groups. same # as the videos of the rebels. there is only propaganda floating arround in the web.
I still think, that the rebels used the gas though. Last time the UN experts came to the conclusion, that the rebels used the gas, so why should it be any different now?