The young man looked up from his receptionist post at the Government Printing Office, his helpful smile abruptly fading.

"A GS-1? Well, gee, I've never heard of any of those," he said before bucking it on to a supervisor who chuckled, "I thought my father was the last one."

At the Pentagon, a voice on the telephone line cracked with laughter. "GS-1? That's the lowest of the low, isn't it? That's like being a recruit in the Army."

And so it went all over Washington. The search for a General Schedule-1 -- the bottom rung on the government's white-collar ladder -- was like trying to find a New Deal liberal in the Reagan administration.

They're out there, 2,393 of them toiling annonymously amid nearly 3 million federal servants -- but GS-1s are now an endangered species, driven from their once-thriving preseve by mechanization and inflation.

"They're messengers or clerk typists or they're sorting mail or learning to sort mail," said Steve Davis, chief of recruitment and information for the Office of Personnel Management's Washington area office. "But you just don't have them when you're talking about complex occupational sturctures. A GS-1 isn't where you'd put in a 30-year career -- or a five-year career, for that matter."

The General Schedule employment category, which ranges from GS-1 to GS-18, applies to white-collar workers and is one of the five types of job-classification systems in the federal system. Depending on education, Civil Service test scores and promotional opportunities, an employe could climb to a top ranking and be earning as much as $50,112 a year. A GS-1 gets paid $7,960 to start, which helps explain why there are fewer than 300 of them in the high-cost Washington area.

Government regulations expressly state that GS-1s are to perform their duties "under immediate supervision, with little or no latitude for the exercise of independent judgment." Given that limited mandate and low pay, there is not much call for or interest in a job that one federal wag dubs "a view from the bottom."

gBut Cathy Lyles, a 17-year-old high school senior from Prince George's County, doesn't see it that way. She has been a GS-1 since last summer and considers the chores she performs for the General Accounting Office to be a valuable learning experience.

"This is my first job," said Lyles, who works in GAO's civil rights office as part of a federal "Stay in School program. "My teacher told me about it and I went for an interview and I got the job. I do light typing, a lot of Xeroxing, answer the phone, and open and sort the mail."

Working four hours a day after attending classes at Northwestern Senior High School in Hyattsville, she makes $3.83 an hour and takes home about $130 every two weeks. She says she has definite plans for the money.

"We have a lot of senior dues and a senior trip [to Disney World in Florida], and I didn't want to put it all on my mother," said Lyles, who hopes to keep the job full time after graduation and to eventually move up the Civil Service ladder.

Student trainees such as Lyles are the most easily located and most numerous GS-1 group in the Washington area. They are anxious to get a foot in the government's door, and they don't sneer at the relatively low take-home pay.

"I'm better off in this job than a lof of my friends are who are working at McDonalds for the minimum wage," said Pamela Malone, 18, a senior at McKinley High School in the District. "I feel I'm getting good experience, and I'm making more money than they are."

Malone, who works afternoons for the Forest Service's "Woodsy Owl" program, sends out antipollution and antilitter kits to students and teachers who request them, types on a word processing terminal, and answers the phone. She plans to take the Civil Service exam this summer, move into a GS-2 federal job and attend college in the evening.

During the past 30 years, the number of beginning-level federal civilian employes has dropped from 12,288 in 1950 to a figure that has hovered around the 2,000 mark for the past 10 years.

"What's happened is that a lot of what used to be traditional GS-1 or wage grade blue-collar work is now being contracted out or taken over by machines," OPM's Davis said. "We don't have our own guards or janitors anymore. We don't have manual elevators. In the mail rooms, we even have automatic letter openers and automatic letter sealers and stuffers."

The GS-1 jobs that do remain, Davis added, are usually restructured to include more complex work and opportunities for advancement "because people are unwilling to take a government job at the minimum wage if it tops out at that." This is particularly true in Washington, he said, where the high cost-of-living demands better pay to attract workers.

"I don't think there are more than five or six persons here who will be a GS-1 for life," Davis said."They are extremely hard to find because even a lowly messenger at a GS-1 [level] would become a GS-2 within three or four or five months." An exception to this, he said, would be some of the mentally handicapped and retarded trainees who work for the government as messengers.

The vast majority of GS-1s are scattered around the country, usually more in rural areas, where a federal government paycheck goes farther. A beginning job emptying bedpans at a veterans hospital or carrying messages at an agency's regional office can look a lot more attractive "if you're in Winchester, Virginia, or Ames, Iowa," Davis said.

In Washington, however, they are a vanishing breed.

"I've never met any myself," said Ellen Murphy, an Internal Revenue Service spokeswoman, as she began the search for GS-1s in her department. She called back several days later to report that she had finally "tracked down this elusive creature."

Her find turned out to be Marthetta Gamble, 16, from Bladensburg High School in Prince George's County. Another student trainee, Gamble works in the IRS personnel office and is saving her money to start college in August.

"Ifyou're doing something wrong, they tell you. If you're doing something right, they tell you, too," she said of her supervisors.

Barbara Coughlan, of the Treasury Department's personnel office, was fairly certain there would be some GS-1s shredding money at the Bureau of Printing and Engraving. As it turns out, money shredders must be the equivalent of a GS-7.

"It's not a question asked but once in 20 years," said Margaret Tackley of the Army's public information office. After several phone calls and with the aid of a computer, she was able to put the number of Army GS-1 civilians at 520 worldwide. Another Pentagon spokesman, Bill Caldwell, narrowed his Department of Defense search to "seven in the whole building -- and I'm trying to find one, but it's hard."

"There's not a one here," said Ed Kittridge, a spokesman for the U.S. Customs Service. "But we seem to have a number of these people in Boston."

At the Department of Health and Human Services, spokesman Moses Newson combed through a computer printout while tireless stalking his GS-1. Phoning in progress reports along the way, he eventually could say with authority that there were more than 50 such persons "someplace," but not in Washington,D.C.

"I thought I had found one out of Rockville, but it didn't turn out," Newson said apologetically. "Sorry about that."