Only a month ago, Barry Gottlieb was living in obscurity in Richmond, scrambling to sell his golf shirts bearing a dead, upside-down alligator on the left breast to anyone willing to take a chance on his newspaper ads and mail him $14.45.

Then, quite unsought, success was thrust upon Gottlieb and, overnight, sales doubled, dozens of radio, television and newspaper people were begging for interviews, and a national movement was venerating him as something akin to a cult figure.

His secret?

"I got sued," Gottlieb said last week from a Richmond telephone booth after managing to persuade a TV reporter that he needed a break so he could squeeze in his 45th media interview of the month. His courtroom opponent: Lacoste Alligator S.A., manufacturer of Izod casual wear, bearer of the familiar (and right-side up) alligator.

Gottlieb describes the battle lines as if he were another Rocky and Lacoste a cocky and disdainful Apollo Creed. In one corner is Gottlieb the challenger, a 31-year-old entrepreneurial eccentric and erstwhile rock musician, fondly called Mad Dog by friends (he says it has something to do with his foaming at the mouth when excited), whose couple-of-thousand-dollar investment a year and a half ago only managed to "keep food on the table." Until he was sued.

And in the other corner, the heavyweight preppie cham-peen of the woild, Lacoste Alligator, a multinational clothing conglomerate based in Switzerland with gross sales in the multimillions of dollars here and abroad, which is intent on protecting its rights to all logos of "lizard-like" appearance.

Lacoste weighed in on April 16 when its attorneys filed a suit in Richmond's federal district court against Gottlieb's Mad Dog Productions Inc., alleging infringement of its alligator trademark rights.

Mad Dog's been trying to figure out what hit it ever since.

"We've had more publicity on this than anything else we've filed" against individuals and companies for trademark infringement, said one source close to the Lacoste effort. "Gottlieb must have one hell of a PR guy working for him."

"Nope," chortles Gottlieb. "Just me."

Yet, not even Gottlieb can explain why the suit against his company, which a source estimates has sold between 30,000 and 35,000 shirts in 18 months, has fired the imagination of so many. But he's willing to bet that it has something to do with the fact that Lacoste alligators are part of every preppie's wardrobe.

"The whole preppie thing became so silly and absurd," said Gottlieb. "First they had the alligator on shirts. Then, the next thing you know, it's on hats, and socks, and maybe even underwear. People just had enough."

It was his own disgust with the preppie movement, plus his penchant for what he describes as taking the ridiculous and making it absurd, that spawned the idea for the dead alligator. It was simply, he said, a business exercise that led him to line up shirt manufacturers, someone to stitch on the logo and then to hit the advertising circuit. But it was Lacoste's suit that made him and his shirts stars.

"If business keeps up like it has, I may have to hire a full-time helper," said Gottlieb with relish.

As far as Lacoste is concerned, however, it's all very serious business.

"If everyone and his cousin can do cheap imitations, the alligator mark loses some of its distinctiveness," explained one company source. "On top of that, people could think that because it Gottlieb's dead alligator is so similar that Lacoste authorized him to use their symbol."

The source said that, since 1980, the company has had to vigorously defend its alligator logo against a host of American and international usurpers. "We've filed maybe 10 to 12 suits in that time," said the source. "You've heard about alligator shoelaces? And the preppie survival kit which had an emergency spare alligator in it? And preppie bumper stickers with the alligator?" One by one, Lacoste has won consent decrees, or the challengers have backed off.

The 1980 date coincides with the publication of "Preppie Handbook," a nationwide bestseller devoted to defining preppieness that has sold some 1.5 million copies. The success of that book, written by Lisa "Bunny" Birnbach, inspired Ralph Schoenstein to write "The I-Hate-Preppies Handbook," a takeoff. That sold a modest 150,000 copies but, as Schoenstein said, "that's more than anything else I've ever written."

"We weren't allowed to use an alligator on the book cover because of the trademark thing," Schoenstein said. "The Simon & Schuster lawyers got nervous." All the same, his heart is with Gottlieb. "Preppies were boring the whole country," he said.

In the meantime, Gottlieb is hardly fretting over the anticipated court encounter, which he is convinced he will win.

"How seriously can I take the whole thing?" he asked rhetorically. "Hey, I think it's going to get a lot crazier before it's all over."