I think it is more likely they were made in Iraq.
Certainly likely, too, but the US is hiding something pretty awful in Benghazi and is willing to go to extreme lengths to keep people from talking and for the facts to come out.
Why would Assad want to use chemical weapons when he has WMDs that strike fear into the hearts of Obama and the Democrats in Congress.
The weapon is that the knowledge that the chemical weapons in his arsenal came from Saddam Hussein's missing arsenal of WMDs that were transferred from Iraq to Syria by the Russians in a Secret deal with the Bush Administration that Democrats, Including Barak Obama himself, had full knowledge of.
The Democrats knowingly and cynically lied about Saddam's missing WMDS and coined the “Bush Lied, People Died” meme, all the while knowing exactly where Saddam's missing WMDs were and that they could lie with impunity because President Bush was an honorable man who kept his deal with the Russians to keep the transfer of Saddams WMDs a secret if the Russians would convince Saddam to sending them to Syria “for safe keeping until the situation with the US blew over”
This would expose Bush as true Statesman of Churchhillian proportions and the entire Democrat Congress as treasonous weasels who knowing lied to undermine both Bush and the War effort.
As a result, they encouraged the development of an Iraq insurgency and definitely got hundreds if not thousands of American and coalition soldiers killed and destroyed Bushes plan for a peaceful post war Iraq
This is precisely what will happen if Assad exposes all of the Chem weapons in Syria. On the other hand, he has leverage to disclose only what he wants and to keep the rest as long as keeps Saddam's WMDS under wraps to avoid exposing the Democrats.
Lots of Democrat Congress critters soiling their undies at the prospect.