The Israelis may have used the aircraft. The capabilities claimed by the program would support a fixed-target strike from a main base. However, the S-300 has been around for some time and I would expect that the IAF already had ways to deal with it.
The question is whether this operation indicates that the contractual requirements for F-35 SDD completion, including a formal IOT&E, are mere bureaucratic pettifogging or whether they actually matter. I suspect that they do, when it comes to sustained combat and training with normal contractor support.