Life," SAYS the fatalistic Shah of Iran, "is like the game of backgammon. You can win big or you can win small. Only part of it is skill, the rest is chance."

Holding-forth at a party in Mexico City the exiled Shah told guests at his table that he still expects fate to one day return him to his Peacock Throne.

Backgammon, he said, was developed by a Persian ruler who had received an elaborate chess set as a gift from an Indian maharajah. Not wanting to be outdone the Persian, according to the Shah's legend, put the best brains in his kingdom to work to come up with something as challenging.

They created backgammon, he said, "the game of life, in which knowledge, faith and luck determine who is going to be a winner and who is going to be a loser."

At the same party the Empress Farah Diba told a group of women guests the things she misses most have nothing to do with the riches of a royal life style or the power of a ruling monarch. The things for which she grieves, she said, are the things money cannot replace that had to be left behind when she fled: family mementoes, photo albums and personal items that would have no value to anyone else.

Maybe the face isn't familiar to readers of any magazine except Playboy, but the current Dewar's Scotch Whisky "profile" in their ads is known in Washington for a semi-nude pictorial layout in that publication three years ago.

That fact is omitted from the biographical data supplied for 29-year-old Raisa Scriabine, while other facts are just a wee bit inaccurate.

Scriabine, a Russian-speaking, German-born blond, left the Interior Department last year to form a company called Forum International for Cultural Relations. Dewar's claims that her most "Recent Accomplishment" was helping to "negotiate and international convention for the Conservation of Migratory Birds" and that in her spare time she paints well enough to have "two major New York gallery exhibits to her credit."

An Interior Department official says that all she did was act as an interpreter for the convention. As for her art work, she says Dewar's made a "tweeny" mistake. Her pastels were exhibited in Ithaca, N.Y., when she was attending Cornell University.

Also, that isn't her office, or even a Washington setting, in the background. If the scene looks familiar, it is because it is the New York City Public Library, which the mayor's office likes to see rented out to still and movie photographers for $200 to $1,000 per shooting hour. Parts of "Network" were filmed there. So were scenes from the new "Chapter Two."

The Library of Congress isn't nearly as obliging and wouldn't let Scriabine be photographed there, with or without her clothes.

Travis Burns Steward, lobbyist for Hoffmann-La Roche, whose division, Roche laboratories manufacture valium, is having what he calls a "collision of friendships."

He is a Georgian whose loyalties to Jimmy Carter date back to the days when Carter was serving in the state legislature and Stewart was employed there. Until recently, his pretty wife (who never fails to get a lipstick-smearing kiss from the President at White House gatherings) was telling friends that "TBS" was going to be joining the 1980 campaign as a full-time fund raiser.

Not so, says Stewart, who has gotten very close to Sen. Edward M. Kennedy's staff as they did health legislation research. Not only is Stewart not joining the Carter campaign, he is saying that he is only "98 and one-half percent" convinced that Carter will be running.

Added to President Carter's other popularity problems are the grumblings of some of his Secret Service agents about the allegedly "arrogant" way he treats them. One of Carter's aides, asked about the complaints, treated the inquiry facetiously: "You must have been talking to the guys who pull night duty at Camp David. I know they've been bitching about his jogging out the door every morning just as they're getting ready to go off duty and they're sleepy and tired and they have to bolt after him into the woods. . ."

. . .It wasn't a thatched roof, but it was a grass one that was discovered growing atop the National Press Club. Thirteen marijuana plants, not quite ready to harvest, were found when someone went up to check for possible hurricane damage. The owner of the illegal little garden plot remains a mystery. . . A bomb scare might send some men looking for the nearest bar. But when Bob Hope had to vacate the Kennedy Center on Tuesday night while police made a search, he headed for the Howard Johnson's across from Watergate, where he downed three double-scoop cones of vanilla ice cream to calm his nerves. . . In the Congressional Record of Sept. 5, on page S11923, there appears "Interpretive Ruling Number 190." It answers the question "Would proceeds from the sale of a Member's phonograph album be exempt from the limitation on earned income imposed under (ethics) rule 44?" Boiled down from two paragraphs of legalese, the answer is "yes." So Senate Majority Leader Robert Byrd gets to take home the profits from his new fiddling record.

. . . The Securities and Exchange Commission is trying to find Saudi Arabian businessman Adnan Khashoggi's wife, Soraya, to serve her with a subpoena. Investigators hope she hasn't reconciled with her husband. He has a blackbelt karate expert named Soo Lee who goes into his kicking and chopping routine everytime anybody comes near the boss with a piece of paper in his hand. So as not to impede bonebreaking skills, Soo Lee goes barefoot everywhere, whether on hot desert sands or icy New York pavements.