Gerry Cooney's people are walking around town wearing baseball hats with the slogan, "Tick . . . tick . . . "

It's supposed to signify the passage of time and its wearing effect on the heavyweight champion, Larry Holmes, whom Cooney fights for the World Boxing Council title on Friday night.

But Holmes and his camp believe time will be the enemy of Cooney instead--time in the ring, boxing for keeps, and the challenger's perilous lack of it.

Cooney's manager, Dennis Rappaport, a real estate man from Long Island, likes to cite figures. "Of the last 33 heavyweight champions," he says, "the average age was 28 years old when they lost the title. Larry Holmes is 33. The clock stands still for no one, and that includes Holmes."

Holmes, in fact, is a fit 32. His trainer, Eddie Futch, believes a more significant and debilitating measure of time is the 13 months since Cooney, 25, last entered the ring in competition.

Futch thinks Cooney's handlers couldn't have picked a worse matchup for their 6-foot-6 slugger's return.

"Take away the importance of this fight," said Futch. "Say it was just another bout and you're bringing back your fighter after a 13-month layoff. What opponent would you get?

"You certainly wouldn't get him a Larry Holmes-Muhammad Ali type of fighter. You don't want him in there with a boxer; a shifty, mobile, experienced fighter with a good left jab.

"Why? Because his timing, his judgment of distances and his reflexes are going to be off from the layoff. What he needs is to get in the ring a couple of times with a target. But our guy gives him no target. He moves, he feints, he counterpunches.

"This is something I've been through many times with my fighters. If my guy's been off for a while I say, 'Get me a match with somebody who can stay in there seven or eight rounds, but don't send me anybody shifty. I want my guy to have two or three fights before that."

Cooney's last fight lasted 54 seconds, as he pounded Ken Norton mercilessly in a first-round knockout May 11, 1981. Before that he had knocked out Ron Lyle in one round in October 1980. Of course, he's had plenty of time in the gym, sparring.

"Sure," said Futch, "but it's completely different when you put on the small gloves and take off the headgear, when you feel the tension of the crowd and you know if you're hurt, no one is going to call time and bring you back to your corner. You're going to have to defend yourself. This is for keeps. I don't care if you have a twin brother ringside. He can't help you."

Holmes, by contrast, fought 29 rounds in 1981. He went the full 15 rounds to win a decision over Trevor Berbick, knocked out Leon Spinks in three rounds and rebounded from a knockdown to beat Renaldo Snipes on an 11th-round technical knockout.

When the Cooney fight was postponed from its original March 15 date, Futch said it was all he could do to keep Holmes from scheduling another bout to fill in during the delay. "He doesn't like being idle that long," said Futch.

"Tick . . . tick . . . "

Mere age has never meant much to Futch. He is 70 years old, although to see him you might guess 50. In more than a half-century in the ring he has trained nine champions, including Ken Norton, Joe Frazier and Alexis Arguello.

Holmes is happy with Futch, but he felt that for this important fight (the paycheck could go as high as $10 million per fighter) he could use some additional help. So he hired an assistant trainer, Ray Arcel.

All Arcel has done over the years is train 19 world champions, including Roberto Duran and Ezzard Charles. He's had a lot of time. He first worked a corner in 1917.

Arcel is 82.

This morning Holmes followed his normal regimen, convening his entourage at 5:30 a.m. and departing the glittery gloom of Caesars Palace for two miles of roadwork where the desert meets the red mountains west of town.

Holmes drove the yellow rental van. Then he ran two miles into the sunrise. Arcel and Futch were right behind, race-walking and nipping at the champion's heels.

"See," said Arcel, "I used to run cross-country in high school."

Sixty-seven years ago.

"Tick . . . tick . . . "

Arcel says walking into the ring after a long layoff is like giving your first public speech. "Remember that?" he says. "It's like there's a mist in front of your face. You couldn't see the faces. Everything is happening too fast.

"It's the same with a fighter. It takes time and experience to be able to see what's going on in the ring; to know what you have to do if you're hurt without thinking about it."

Both he and Futch think rebounding from an early damaging blow is a circumstance Cooney will have to confront.

"Here's a fact most people ignore," said Futch. "Good fighters love to fight one-handed fighters, and that's what Cooney is.

"You just wait for him to use that left hook, and every time he does you go over the top and try to tear his head off. You hurt him every time he uses that hand. Then he's concerned about getting hurt. He gets defensive. You're taking away his best shot."

Arcel thinks the only way Holmes can lose is "to get careless, like he did with Snipes. Let's face it, this guy (Cooney) can punch. But if this guy hits Larry Holmes, who is an excellent boxer, then it's shame on Larry."

The oddsmakers agree. Holmes is the betting favorite here by about 3-to-2 odds.

"Tick . . . tick . . . "