The Sunday Times says yes, although they (a) don't elaborate on its enormous significance and (b) inexplicably bury it in the middle of the story:

Bush's refusal to give Israel the US's Identify Friend or Foe (IFF) codes - the codes that aircraft broadcast to let allies know not to shoot them down - has long been one of the most obvious reasons that Israel could not get all the way to Iran. There was even a rumor going around at the beginning of the year that Israeli jets heading towards Iran were turned back before they got into Iraqi airspace because they couldn't get the codes. And of course, notoriously, Bush and Baker's refusal to give Israel the Coalition's IFF codes prevented Israel from retaliating for Saddam Hussein's unprovoked SCUD attacks (historically Christian and Muslim nations attack another Muslim nation - and the Jewish State is expected to sit there and get bombed - why not, right?)

Regardless - of all the reasons to believe that the Syrian air strike was a dry run for Iran, Israel's possession of US squawk codes is certainly not the least significant.

References:
* Israelis ‘blew apart Syrian nuclear cache’ [IsraPundit]
* The Countdown To An Iran Strike Has Begun In Jerusalem and Washington [MR]
* Iranian President Derides U.S. Threats [Jihad Watch]

Previously:
* OneJerusalem.org Conference Call: Pastor John Hagee, Senior Pastor of Cornerstone Church [FAQ: Debunking Liberal Myths About Evangelical Support For Israel]
* Purdue Nuclear Strategy Expert: Bomb Iran Now
* Former Israeli Intelligence Official: Iranian Facilities Being Hardened "Around the Clock", Time Running Out