For the past 14 months, G.R., Conley Associates appeared to be just another corporate group renting a second-floor suite at the Shoreham Americana Hotel. It paid its $1,500-a-month bills on time, had occasional visitors, and kept its bar well-stocked with liquor from room service.

Unknown to the hotel, however, G.R. Conley Associates were undercover law officials posing as fences and their customers were thieves bringing stolen merchandise to sell the undercover men, usually in view of a skillfully hidden videotape machine.

Occasionally, however, the merchandise was too big to deliver to the suite. The undercover agents took delivery on a truckload of stolen property that included mirrors, from a U.S. Capitol warehouse, in a parking lot. A collection of 16 antique rifles valued at more than $5,000 was switched from one automobile trunk to another outside the hotel.

Details about the fencing project, which was unveiled by the police and FBI Saturday as Operation High-roller, began to emerge in federal court yesterday as bonds were set for the first three defendants here.

A total of 16 warrants were issued in five East Coast states and D.C. and 12 persons have been arrested so far. One defendant was shot to death in Richmond in a gunbattle with police, and three others are still at large, the FBI said.

Assistant U.S. Attorney Lawrence H. Wechsler of the major crimes division yesterday argued successfully for high bonds for the three defendants, claiming they were likely to flee because of the strong videotaped evidence against them.

U.S. Magistrate Lawrence Margolis set the bonds on the following derendants, who were arrested at the Shoreham Saturday;

Lynn R. Adams, 30, of 13808 Newport La., Chantilly, Va., who was ordered held on a $50,000 surety bond on charges of selling $105,000 in stolen U.S. treasury bills and bonds.

Edward M. Marra, 30, of 174 Manassas Dr., Manassas, Va., who also was ordered held on a $50,000 surety bond on charges of selling antique mirrors stolen from the warehouse where they were stored since being removed from the U.S. Capitol in 1854.

Orville White, 43, of 5100 Monument Ave., Richmond, held on $15,000 surety bond on charges of selling a stolen antique gun collection and stolen antique china collection.

Wechsler described Marra and Adams as "partners" who were paid nearly $36,000 by the undercover police agents for property.

The men, both of whom described themselves in court records as unemployed excavation workers, worked together to bring in the antique mirrors, treasury bills, bonds, and stolen cars, according to affidavits and court statements by Wechsler.

The cars were stolen from rental lots at Dulles Airport and were valued at $24,000, investigators added.

According to affidavits filed supporting Marra's arrest, he called a Highroller FBI agent on May 27 of lst year and told the agent that antique mirrors from the U.S. Capitol "would be stolen from where they were stored." Marra allegedly sold the mirrors to the agent on June 12.

Attorneys for Marra and Adams argued that the men have no prior records, have lived in the Washington area for more than a year, and were eligible to be released on their personal recognizance. The wives of both men were in the courtroom.

White came to be known to the FBI agents and police under the names of "Howard Knight," "Clyde," and "O," according to the affidavit in support of his arrest.

He described himself in court as a harvester of soybeans, who lived in Richmond when there were no crops to be harvested in the South and Southwest.

The affidavit said he sold antique rifles to the officers that had been stolen from a well known gun collector in Richmond. The gun collector had previously reported his home had been burglarized of the 16 weapons, police said.