The U.S. has worked very hard to keep F-14 spare parts from Iran. But there isn't a snowball's chance in hell of blocking F-4 or F-5 parts. There's just too many in scrapyards around the world.
I wonder why Iran isn't considering the Chino-Pak JF-17?
JF-17 uses the same engine as the Mig-29, which Iran operates. If I were Russia, Id rather they buy Migs.