As Craig Stadler, the leading money winner in golf this season, walked into the grill at Congressional Country Club yesterday after his practice round before the Kemper Open, an inconspicuous white-haired gentleman approached him.

The fellow had been sitting alone and unnoticed, reading the Wall Street Journal and carefully measuring the salt he put on his food.

That's when Stadler's wife, Susan, eagled the 19th hole.

First, she rolled her eyes to get her husband's attention, then, in a mimelike stage whisper, she said, "That's Mr. Kemper."

Taking his cue perfectly, Stadler grinned at the chairman of the board of The Kemper Group and said, "It's good to see you again, Mr. Kemper."

Even zillionaires like to be remembered.

The world is changing quickly for Craig Stadler and, to the surprise of those who thought Stadler a brusque harsh-tempered fellow, the Walrus is adapting nicely to his new fame.

These days, Jim Kemper wants to shake the hand of the reigning Masters champion and defending Kemper Open titlist. Stadler goes out of his way to be gracious.

Crowds gather behind Stadler as he hits balls at the range. When a fan says, "Hey, Craig, come here a second," Stadler doesn't glare, but, rather, smiles and says, "I'll be with you in a few minutes."

Everywhere he walks at Congressional, where he broke the course record by five shots last year, a gantlet of autograph seekers forms in front of him. Stadler gives each a sliver of attention, answering their inanities with civilities. Can he can win here again when the tournament starts Thursday? "Hope so. Don't see why not."

As he steps into the locker room, Stadler is accosted by a reporter. When is a good time for him to talk? "Is there ever a good time?" he says, unable to suppress his honesty. Then he says, "How about right now?"

Next, he's glad-handed by a representative of the biggest agent in sports, Mark McCormick. Stadler lends an ear, just as he's listened to get-rich guys from all over the world ever since, after winning at Augusta, he mentioned he'd never had a manager.

For everybody--from the 10-year-old whose ballpoint pen won't work to the sponsor of this $400,000 event--Stadler has the same cheerful greeting. A smile plays under the rusty mustache and the eyes, characteristically aimed at his shoetops, cut up to look each person in the eye.

A year ago when he arrived here, Stadler was just another player with potential who'd left no mark as yet.

Now, after winning two tournaments and nearly $240,000 in half a season, Stadler stands on the edge of fame. In '82, he's also been second twice, as well as fourth, fifth and sixth. At 29--today is his birthday--Stadler is at the fulcrum of his career.

Two weeks after the Masters, Stadler stunned golf by honoring a commitment to play in two tournaments in Japan. Many would have jilted those foreign sponsors, stayed stateside, raked in big fees and kept their game sharp.

"I could have stiffed 'em," says Stadler. "Going to Japan is definitely not what I would have chosen to do right after winning the Masters. But, I had a commitment. And we certainly had a good time in Japan."

What Stadler got in Japan was a swing so quick and sloppy that, when he returned to the tour at Colonial and Muirfield, he finished 58th and 62nd, failing to break par in any of his last eight rounds.

"I've been terrible," said Stadler. "But, it's been getting better and today I was actually hittin' it pretty good . . . You can say I'm kinda close and getting closer. I'm getting excited again for the first time since the Masters."

A temporary swing flaw doesn't bother Stadler as it once might have. He's been through the ultimate choke inferno--the final nine at Augusta--and survived. "I hit a lot of decent shots coming in and still made some bogeys," said Stadler, who shot 40 on the back. "I'll admit I did have one negative thought. When I hit a perfect drive at 17 and it rolled into a divot, I looked at the ball and said, 'Good Lord, what do you have to do to win this thing?'

" . . . If there was any choke in me, and I don't really think there was, then it was on the 18th (three-putt) green . . . it would have been nicer to win going away by four or five shots, which I think I should have, but it doesn't matter how many."

If peace of mind is of help in coping with celebrity, then Stadler has a fighting chance of turning his current fame into lasting accomplishment.

Before he ever got to the clubhouse yesterday morning, Stadler relieved his caddie of the huge golf bag and lugged it himself through the catacombs of Congressional. Watch all day and find another player, even a rabbit, dragging his own 50-pound sack.

"Craig doesn't come off as the way he really is," says his caddie, Joe Brennan, a Rutgers graduate student. "He just gets brutally misjudged. He gets mad at himself, but he doesn't have a bad temper toward other people. He's a very honest, down-to-earth guy who'd be perfectly happy as a stockbrocker where nobody knew who he was.

"He doesn't need all this fame . . . But he's conscious he has to work harder at not coming across as gruff and angry."

By teeing off in the dew, playing only nine holes and stopping practice before noon, Stadler was able, as usual, to put first things first yesterday. "I'm taking the short one to the zoo," said Stadler, speaking of his 2-year-old son, Kevin. "That is, if I can find Connecticut Avenue. I usually have a good sense of direction."

As he got to his locker, Stadler spied young Kevin, who'd ferreted out his father. "Kevin, where are you?" Stadler asked.

"In a locker room," whispered the boy.

Stadler scooped up the little child, then observed cheerfully, "Ahhhh, soaked."

Everything was right, even wet bottoms, in Stadler's swiftly changing world. As usual, his sense of direction was true. The walruses were waiting; it was time to go to the zoo.