Billy Carter cracked open a can of Dixie beer, swigged and smiled as he looked at the exhibit of Phillip Sage etchings of his hometown.

"I'm not sure whether they're paintings or not," he said. "I hadn't known what etchings were until Phillip told me. I used to think they were what dirty old men used to get girls to come up to their places to look at."

Sage went to Plains last year, said Billy, "before there were 800 people everywhere," and collected material for a series of etchings of the First Family's native land called "Carter Country."

The first six opened here yesterday at the Hyatt Regency Hotel, along with Barbara Coleman's color photos of the area and a collection of Jimmy Carter campaign buttons accumulated by Maxine Reese. She organized the "Peanut Special" train to Washington, D.C., for Carter's inauguration.

The etchings on display show the Carters' mother, "Miss Lillian;" downtown Plains; the Plains Baptist Church; a sharecropper, John Henry Holly, and his dog, Spot; the Plains railroad depot; and the town's only men's club - the backroom at Billy Carter's service station.

Billy Carter is in the middle of that etching, wearing his red jacket with an STP patch, and he was so pleased with the result that he signed it. At the reception yesterday peanuts were served in silver bowls and bottles of Jacques Bonet champagne were poured into clear glasses while the Bad Oyster Band thumped out blue-grass music on a gut bucket, wash-board, several kazoos and a pair of spoons.

Carter sipped the champagne, but he stuck with the Dixie beer, saying. "The thing I like best about New Orleans is that the bars open at 8 on a Sunday morning."

In addition to the exhibit, Billy Carter and his wife, Sybil, saw a Mardi Gras parade, and, he said, "I almost got beat to death with the stuff they were throwing off the floats."

Sybil Carter wore a string of purple beads picked up from the parade and stood to one side while reporters, photographers political types and hangers-on gathered around her husband.

Since last year's campaign Billy Carter has become a folk hero, and many think the media has made too much of him, but his wife says, "That's a misconception. Nobody takes over Billy.

"He had to roll with the punches, and he likes it, but when he's had enough, he'll say, 'Enough.'

"He can be serious but he's always been like this."

As people clustered around him, Carter signed everything in sight, including the first can of Dixie beer that he drank. That prize went to Bill Parrie.

Among those greeting him was fellow service station owner Dan Usner, president of the Louisiana Service Station Assn., who was pleased at the publicity his profession has been getting.

Said Usner: "It's great. If he maintains his standards, we could all stay in business."

But his secretary, Therese Durel, added, "We just have to open a back room."