Perhaps, perhaps not.
It is a matter of intelligence. There is ALMOST ALWAYS some key facility, which, once knocked out, brings the entire project to a stop.
Frankly, I suspect Israel will target the Iranian leadership rather than the nuclear sites. In Iran, the crazy mullahs who run the dump are fairly accessible to assassination. They are constantly in the public eye -- hence in the possible cross-hairs of the assassin.
If Israel could target a meeting of the head honchos, it could weaken, perhaps cause the collapse of the Iranian government. It would certainly cause some consternation.