A general consideration about Iran defence forces: there are a lot of derogatory comment about their achievements talking about 70' level tecnologies.
Well, they seems me to miss two or three points:one is about medium and top level of tecnologies, Iran has a very large armed forces so they can't simply equip all them with the latter still beside F-14 and even F-4 has also eighty or more mig-29 in its inventory so they have reached almost the same generation of f-15 and f-16.
Second, they are under embargo from decades and still can autonomosly operate, mantain upgrade and even produce many different sofisticate (an jet fighter, even from seventies is such of a thing) weaponry: for what I know none of the gulf monarchies directly opposed to them can even dream about any of these thing.
Third also today with a stiffed up embargo, they still receive consistent support from Russia and China, not in form of direct weapon purchase ,but with state of art electronical components and software updates that given the second point is fair enought.
Obviously they usually grossly exagerate performances of their weapons for propaganda pourpose, descriving all of them like out of this world marvels, but assuming like someone here that their own tecnological level is still those of '79 means exactly just another way to fall head down in their propaganda.
Before the fall of the Shah's Iran received 6 RH-53D but may be as Desert One is surely one of the survivors of this batch of 6 aircraft delivered in the 70. Al menos 1 de los Desierto Uno esta en servicio