Come on! SA-2s are very old and huge missiles with a lot of units to operate and I do not think that it is something for Israel Air Force to worry. If Syria hands over the old SA-2 batteries in her inventory to Lebanon, it is just because they are obsolete. But it seems not very weird to sell/transfer arms from one country to an other (Syria to Lebanon). Despite all these facts, if this happens, it could be a good reason for Israel and good training opportunity for IDF to burn the south half of Lebanon and kill some thousands civilians as usual.
Report: Palestinian, 18, killed in clashes with IDF in West Bank (Haaretz)
from the article: U.S. official: Arming of Hezbollah could spark Israel-Syria war