When the fashionable members of the horsey set gather in Laurel's dining rooms this weekend, the owner of the top money- winning horse in the Budweiser International will grudgingly put on a sports jacket to join them. After all, he says, it's a free meal.

But Charlie Linhoss would be more comfortable spending the climactic day of the International Turf Festival the way he spends just about every other day at Laurel: wearing a T-shirt and hanging out with his cronies in the grandstand. That's where he hung out before he bought the horse Ten Keys for $14,500, and that the animal has subsequently earned $1.2 million has not altered his outlook on life.

Linhoss is a carpenter by trade, and the irregular hours that he worked doing home renovations and odd jobs gave him plenty of opportunities to go to the races. His main love was thoroughbreds, but it was one night at Rosecroft Raceway that changed his life.

The harness track then offered an exotic wager consisting of two exactas and one triple; the jackpot had been building up, and on the night Linhoss went to Rosecroft the pot was going to be paid off to whoever came closest to a perfect ticket. Linhoss hit the two exactas, but his horses in the triple finished 1-3-2 instead of 1-2-3: close but no cigar. The carpenter went home disgruntled, but when he picked up The Post the next day he read that only one ticket had even picked the winner of the triple race, and that it was worth $40,000. That ticket was still in Linhoss's pocket.

Upon learning that he was a man of relative substance, Linhoss did not pick up the phone to call a stockbroker about municipal bonds. He called trainer Michael Pino.

"I'd been coming to the track for years," Linhoss said, "and I'd always thought how great it would be to own a horse. A friend of mine had a couple horses with Mike, and so the next day I looked Mike up, told him I'd made a few bucks and told him to start looking for a horse."

Pino had been a trainer for only three years, and dealt mostly with cheap horses, but he proceeded to make one of the greatest claims in thoroughbred racing history. He had recently won a cheap maiden-claiming race with a horse he liked, but he noted the second-place finisher had had a very tough trip and probably deserved to win. The horse was Ten Keys, and when he made his next start, Pino put in a claim on Linhoss's behalf. They acquired the animal for $14,500.

Within a few days, Pino was telling Linhoss their new horse might be something more than the mid-level claimer they thought they were getting.

"It was a strange thing to say, but he really looked the part of a good horse," the trainer said. "There was something special about him."

Ten Keys won two races at Laurel for his new management but in the spring of 1987, when turf racing resumed in the East, Linhoss and Pino learned what would make the animal special. The first time that Ten Keys set foot on the grass he won a stakes at Delaware Park by six lengths. This was going to be one of those rare, inexplicable cases when a horse was a fair-to-middling performer on the dirt but a tiger on the grass.

Although he might not be quite good enough to beat the best turf horses in the country, Ten Keys was good enough to win plenty of rich stakes, and Pino managed him brilliantly to find the optimal spots. He and Linhoss have traveled with Ten Keys to 16 tracks, winning such far-flung events as the New Hampshire Sweepstakes, the Mardi Gras Handicap in New Orleans and the Bay Meadows Handicap in San Francisco.

It was on one of these excursions, to San Francisco in late 1987, that Ten Keys was horsenapped.

Linhoss recalled: "He'd run third in a race at Bay Meadows; we put him back in his stall and then we went out to eat. We came back the next morning and the stall was empty. We looked in every stall on the grounds and couldn't find him."

Two days later, a trainer at a little northern California track, Pleasanton, found an unfamiliar animal in one of his stalls. He had read about Ten Keys and got the word to Pino and Linhoss.

"Ten Keys is a real people horse," Linhoss said. "He recognized us as soon as we walked to his stall. It was like a big reunion." The mystery never was solved, but those were two of the very few dark days in the whole Ten Keys saga.

The durable horse has raced steadily and consistently for four years and, Pino said, "He's probably better this year at the age of 6 than he's ever been." In Sunday's International, with a field weaker than usual because horses aiming for the Oct. 27 Breeders' Cup won't be in it, Ten Keys will have the best chance of his life to win a Grade I stakes of such magnitude.

Of course, no flesh-and-blood creature can resist the ravages of age forever. Linhoss knows that this wonderful adventure with Ten Keys can't go too much longer. Moreover, he is a diligent enough handicapper and student of the game to know the chances are slim that lightning ever will strike like this again. But a once-in-a-lifetime experience is better than none. Many of the tycoons, heirs and heiresses involved in the International Turf Festival will spend millions of dollars without ever coming up with a horse like the one Linhoss got for $14,500.