It's a little late for apologies, about 20 years late, and Willie McCovey isn't even sure he's accepting any.

Big Mac knows what he's done, even if most folks outside San Francisco haven't a clue.

Any day now, when Old Stretch become the 12th man in history to hit 500 homers, he will do it to please himself and to delight his long-faithful Frisco fans.The rest of the sports world can go to blazes.

It's too late now to get on the McCovey handwagon. Seating is limited, by McCovey invitation only, and it helps to be from the city by the bay.

The 500 Club is even more exclusive than the 3,000 Hit Club. Perhaps none of its members have suffered half the subtle indignities that have dogged McCovey.

Years wasted in the minors, four seasons of his prime semiwasted as a part-time big league player - McCovey had tasted that by the time he turned 25.

In his peak seasons, McCovey was so bedeviled by injuries - major surgery on both knees, and perpetual "minor" injuries from broken arms to pulled muscles - that he only got 500 at-bats in four seasons and more than 540 only once. Hank Aaron, by contrast, averaged 600 at-bats for 15 straight years.

In his baseball old age after turning 35, McCovey was treated like a discard. The Giants traded him for a never-was pitcher, San Diego put him on waivers and Oakland - the Charlie Finley Tar Pits - gave him his unconditional pink slip.

Even now, after being salvaged by his beloved Giants and being voted comeback player of the year in '77 with 28 homers and 86 RBI, McCovey gets slighted. His name, almost unbelievable for a 500 Club man, was left off this year's All-Star ballot.

San Franciscans are so furious that Mayor George Mascone feels it politicially wise to lead the McCovey Write-in Campaign himself.

So how did McCovey fell here Monday night after he had hit his 498th homer and not one reporter came to his locker to ask about it?

"It's a good thing that fame is not what I live for," smiled the 40-year-old, his cheerful moon face radiant, though his words are serious, "cause I certainly haven't gotten a lot of it.

"I've always gotten respect, because I've conducted myself in a way that merits respect. But I'm not as 'nationally known' as a lot of players with lesser careers."

Balance is important to McCovey, whether in keeping his huge batting stroke in sync, or in moderating his disposition. McCovey's two dominant personal traits are personal pride and good humor. They often fight an odd and complex battle for control of his face.

"I'm not bitter," McCovey insisted. Nevertheless, he seldom misses an opportunity, in a level-tempered way, to set the record straight about The Real McCovey.

The contrast between Pete Rose's ballyhooed countdown to 3,000 hits and McCovey's almost unnoticed march to 500 homers is too stark for McCovey to miss. The two accomplishments are almost equals.

"There's no purpose, no good, in pursuing that," McCovey said with a resigned shrug. Then he does.

"You don't see me in any commercials on TV. You don't see me on magazine covers. It's nothing new. It's always been like that. But that doesn't mean Rose had had that much better a career than I have."

McCovey, like many others, has trouble figuring out just how his career does stack up. For two healthy years, 1969 and 1970, he was the best hitter in the game, averaging 42 homers, 126 RBI, a .305 average and 130 walks.

During those rare (seven out of 20) seasons when McCovey stayed in one piece, he averaged well over 35 homers and 100 RBI.

Now when all those partial seasons are finally added up. McCovey's true ability is becoming evident. And McCovey, above all others, is helping that process of addition.

Last year, he passed Stan Musil. This April, Lou Gehrig went by the boards. By September, McCovey assumes he will climb past Mel Ott, Ernie Banks and Eddit Mathews (512) on the all-time homer list. Big names, every one.

That's only part of the plot. McCovey has come to a gentleman's agreement with the Giants for a 10-year personal service contract to play, then coach and promote.

"I expect to play until 1980," he said, knowing that will make him the fourth man in history to play in four different decades. "And I'll be a regular as long as I play."

That means, with any luck, McCovey will surpass Ted Williams Jimmy Foxx and Mickey Mantle (536) on teh swat list and finish his career in sixth place. McCovey's feast has been a long time coming, but Big Mac is going to have his with pickle, relish and mustard if he has to whop the Hall of Fame committee over the head with the record book.

McCovey's old-age batting marks are not a tarnished memorial, like Early Wynn's pathetic 300th pitching victory. The bottom line on McCovey is that, on an at-bat basis, he is one of the 20 best sluggers in history. Maybe one of the five best.

This ratio of a homer every 15.1 at-bats is the fourth best in history. His RBI-to-at-bats ratio would give him 116 ribbies for a 600 at-bat season - the kind he never had.

McCovey has aged with gentle grace. At first base, Stretch still moves like a big cat. His long, sweet swing is a song of leverage and raw power in harmony.

Only one baseball has been in RFK for seven years. It is inside the centerfield clock. McCovey hit a 440-foot liner in the 1969 All-Star game that smashed the plastic face of the clock at the 6 o'clock mark. The hole is still there. McCovey assumes the ball is, too. "I think I hit my other home run that day harder," he deadpans.