True or false?

1) Shah Mohammad Reza Pahlavi keeps a British-built Harrier jump jet in the back yard of his Niavaran Palace and checks out the controls every night-just in the case.

2) Teheran airport was really closed last weekend on the eve of the two-day Ashura mourning marches to prevent the shah's archenemy, Ayatollah Ruhollah Khomeini, from flying in from his exile near Paris.

3) Iranian air force helicopter gunships opened fire on anti-shah demonstrators in Isfahan.

In a nation deprived of newspapers by strikes and still prisoner of the oral tradition, such fabrications are accepted as hard fact even by many educated Iranians long exposed to Western thinking on the laws of evidence.

It is also the heritage of a quarter century of the shah's authoritarian rule-and indeed of local cultural tradition-which scarcely encouraged citizens to exercise critical judgement.

Rumors have contributed mightily to he shah's growing isolation in the country. Opposition psychological warfare experts have combined the age-old gift for half-truth with such modern means of dissemination as the tape recorder, the mimeograph machine and the direct-dial telephone system.

The master coup to date in the field of rumors involved a purported Central Bank document alleging that more than 100 Iranians, many of them prominent in politics or the government-run sectors of the economy, had transferred nearly $2 billion abroad in September and October.

Little did it matter that the Central Bank denied the existence of any such document, does not keep records of this kind or that such transfers would have been legal had they indeed taken place.

The timing was brilliant since it underlined genuine popular indignation at corruption in high places, which no Iranian government has proved willing to punish even if a relative handful of supposed culprits have been arrested.

The best guess is that the document story grew from a clever fake dreamed up by university students working with disaffected Central Bank employes who saw that the list was printed in proper form on official stationery.

By comparison, most opposition and government psychological warfare efforts are crude stuff.

The government, at one point in its unsuccessful effort to rally the support of Westernized middle class Iranians, reported cases of Islamic fanatics throwing acid in the the faces of women who refused to wear the chador, the ankle-length cloak worn by tradition-minded Iranian women.

Another aspect of the problem is the almost mystical powers ascribed to foreign governments in the unfolding crisis.

Iranians' willingness to ascribe a major role to Britain in the current crisis might surprise in the light of the reduced British world role these days. But responsible Iranian executives and high-ranking politicians speak matter-of-factly of the all-pervading influence of the British.

Who else, they reason, knows the country well enough to organize the trouble erupting in one provincial center after another? Who else but the British, they ask with a twinkling eye, have been active in Iran for about 200 years? Indeed, a current joke asks, "What do you see when you pull the beard off a mullah?" The answer: "A stamp saying made in Britain."

What Iranians believe about the British, they believe even more readily about the Americans, whose extensive presence here makes them a natural target of the tendency to seek a foreign source for Iran's troubles.

Government suspicions about the British have deepened with anger at the Persian-language service of the British Broadcasting Corp., which is the only trusted outside source of news.

The BBC Tehran correspondent is regularly reprimanded and the British Ebassy is threatened with possible loss of contracts. A progovernment newspaper cartoon several months ago showed the BBC with the 'C' cleverly transposed into a hammer and sickle.

But this past week it has been the opposition cursing the BBC for allegedly underestimating the size of the demonstrations against the shah.

Yet, the government psywar experts seem to be onto a good thing in the last few days. There's a story going around the country insisting that a prominent Moslem cleric of Mashhad, Ayatollah Ghomi, has had dreams on two successive nights that told him that people are wrong to turn against the shah.

The cleric in question denies he ever had such a dream. But one thing is sure: Iran ever had such a dream. But one thing is sure: Iranians are calling each other up to tell the story. CAPTION: Picture, Iranian soldier in Isfahan, site of recent protests, stands guard in front of a troop carrier decorated with pictures of the shah and his express.