The "revolution" has mellowed. The recent lifting of the two-year-old curfew symbolically ended "the rule of the gun." Now squatters live in the vandalized white-marble Masonic temple, for years a secret assembly hall for the now overturned American-Liberian oligarchy.

During the bloody Army coup two years ago, many persons were shocked by the soldiers' vengeful bitterness toward the class considered exploitative, descendants of the former American slaves who founded the country. But now, after months of political instability, executions of alleged plotters and undisciplined, gun-toting soldiers, Liberia is surprisingly tranquil and seemingly self-confident.

The commander-in-chief and head of state, Samuel Kanyon Doe, 31, bears little resemblance to the nervous master sergeant who met the foreign press for the first time 10 days after taking power on April 12, 1980.

Doe has replaced his army fatigues with three-piece suits that do little to hide a growing paunch. As a richer diet has gradually expanded his small frame, Doe has partially shed his legendary paranoia and adopted a policy of benign, consensus-oriented rule.

Except for a brief, early flirtation with radical Libya, his government has swerved right in its foreign policies--and too close, some critics think, to the American government. The U.S. ambassador, William Lacy Swing, is popular here, maintains a high profile, has easy access to Doe, and according to American diplomatic sources is an effective advocate of substantial American aid to Liberia's financially strapped government.

President Reagan, in a congratulatory message on the coup's second anniversary, invited Doe to make an official visit to Washington. Liberian officials said details are being discussed with the White House staff.

Last December Doe announced he would hand over power to an elected civilian government in April 1985, released the last 19 of 400 political prisoners and granted amnesty to the thousands of Liberians who fled the country after the coup.

"We want you to realize that we did not come to perpetuate military rule," he said of the 22 military men on the ruling People's Redemption Council. "We have no intention to outlive our usefulness."

Doe also admitted that former police director Varney Dempster and Adolphus B. Tolbert, son of William Tolbert, the assassinated president, are presumed dead. He said the two men were led away from their prison cells one night by the late deputy head of state, Maj. Gen. Thomas Weh-Syen, who was himself executed last August on charges of plotting to overthrow Doe.

Both a Liberian banker and a high-level civilian official said several month-long training exercises conducted by American Green Berets with Liberia's 5,000-man Army has resulted in a more disciplined force and a perceptible lowering of tension among civilians.

"When there is a large number of American military personnel present," the banker said, "Monrovia's atmosphere is more relaxed."

The civilian official agreed. "The Green Berets have been effective in bringing order to the Army," he said. "The soldiers are politer, and there are fewer in the streets with guns unless they are on assignment."

A businesswoman whose sister and elderly mother were dragged from their home and slapped around by armed soldiers six months ago said such occurrences are infrequent today.

"Our lives are almost normal again," she said. "The only thing that worries me is the economy."

"For Liberia today, the most difficult economic period is the short to medium term--say the next two to three years," said Monrovia-based Citibank Vice President Kadita N. Tshibaka in April. The economy of the country, which has a population of only 2 million, has been severely damaged by a "staggering" 42 percent drop in bank deposits through capital flight since the coup, he said.

By last March, $74 million had been withdrawn, leaving a minuscule $103 million in deposits. Banks' commercial loans are based on a percentage of their deposits.

"Liberia will continue to be economically depressed for the foreseeable future," said Bonnie Lincoln, an economist at the U.S. Embassy .

Tolbert saddled Liberia with an extraordinarily large debt, partly to finance the summit meeting of the Organization of African Unity in Monrovia in 1979. At the same time, world prices and demand for Liberia's principal exports--iron ore, rubber and tropical hardwoods--have plummeted.

Western government officials meeting in Paris recently agreed to reschedule payment of 90 percent of Liberia's foreign public debt of $216 million.

Although it is faced with a $138 million budget deficit this year, Doe's government gets high marks from banker Tshibaka and economist Lincoln for being fiscally "prudent" and "conservative."

To meet Liberia's financial obligations, Doe's government daily risks domestic turmoil by continuing the Tolbert government's practice of withholding civil servants' salaries for up to three months at a time. Still, every 30 days Liberia comes close to defaulting on its $13 million monthly oil bill. New taxes have been ineffective and Liberia's corporate community gets away with a "grossly undervalued" $13 million annual tax bill, according to a well-informed financial source. "With a little investigation, the government could double" what corporations are paying, the source said.

A Liberian banking source said that widespread corruption continues to contribute to economic difficulties. "Corruption has become institutionalized," the source said.

In an attack on corruption beginning in March, Doe ordered government-wide audits and fired numerous officials on charges of embezzlement or accepting bribes.

In an interview, however, Foreign Minister H. Boima Fahnbulleh denied that corruption exists on a grand scale. "There is petty corruption, yes," he said. "But it is not institutionalized or else there would be no audit."

Liberians are holding a collective breath over the first "positive" findings of a World Bank-financed study of the possibility of offshore oil deposits.

In the meantime, American economic assistance to Liberia has risen "tenfold" since Doe's coup, U.S. Ambassador Swing said. American aid for this year alone totals $70 million. In the last year of the Tolbert government, American aid totaled $5 million.

From the time freed American slaves founded Liberia early in the 19th century, the United States has had close ties to this country, Swing noted in a speech in Houston in October. Taken together, American investments and trade with Liberia average a billion dollars annually.

"This relationship has sometimes been turbulent and sometimes peaceful, sometimes niggardly and sometimes generous," Swing said. "Today, however, with the possible exception of Nigeria, no West African country is receiving greater attention in Washington than Liberia."

Swing's popularity here has grown out of that relationship, according to Foreign Minister Fahnbulleh.

"Our newspapers cover Swing closely because most people here want to know and hear what the Americans are doing in our time of need," Fahnbulleh said. "The lights focus on Swing longer because he is an actor in a very exciting drama during a dynamic period of change."