My guess is that Israeli officials are afraid of Syria playing the Cuban role in a new missile crisis, once Iran gets its nukes up and going. That would reduce Israel's reaction time significantly in the event of a Syrian launch. If online commentary from English language Israeli news sites is any indication, popular opinion in Israel does not favor the Syrian rebels. However, the Israeli leadership is trying to get Assad toppled by hook or by crook before the Iranians get their nukes on line, on the assumption that the Iranians wouldn't place them in a Syria dominated by Sunni Islamists who view exterminating Shiites as the first order of business before embarking on a world tour with Allah's personal assistance (i.e. Koranic catastrophes like plagues, floods, et al, inflicted on the non-Muslim heathens).
a guess (best guess) is they are up and going.