It would cease to exist within about 5 minutes of hostile activities. American missiles can take out Iran's jets from 100 miles away. Iran's planes would be shot down before they even knew they were under attack.
A half dozen F35s, F-18s, F-22s and all the Iranian pilots will be saying is 'Oh crap!' (in Farsi, of course).
Let the Mullahs brag- that's all they can do. They've wasted billions of dollars on supporting terrorism throughout the world while their own population suffers. Pretty soon it will be the Mullahs and the Supreme Council that are crying, "Oh crap!" as the Iranian people take back their country.
Israel's use of the Phantom until 2004 suggests how potent that Vietnam-era fighter-bomber can be in a low-threat situation. It is a real heavy lifter for a fighter, but as others have said, it wouldn't last long against fourth and fifth generation air-superiority fighters; they'd destroy it before the Phantom drivers even knew the other guys were around.
And like all aircraft, age and flight hours require increasing maintenance, and for the Iranian F-4, parts that might no longer be available except by cannibalizing other Phantoms.
In theory, Phantoms flying barely above the waves might get close enough to a U.S. ship to fire missiles at it, but that presumes no U.S. aircraft are flying in the area.