This happened at the height of the major dispute between the U.S. and Iran, perhaps 1980 or 1981.
Bo Corby and crew diverted to I presume Mehrabad airport (Khomeini airport had recently opened) on June 19, 2005 so you might have another incident in mind.
I operated into Mehrabad with an overseas carrier in the 1990's. The folks were warm and helpful. My nationality was incorrectly listed on the gen dec, apparently an agreed 'oversight' arranged locally with operations. It was a turn, some folks went to duty free to get caviar, I always stayed on the plane.
The Revolutionary Guards would come on the plane for a 'security check'. They knew I was a gringo and often teased me 'come, be our guest!' The ground staff was polite and friendly.