If any spies for Roberto Duran dropped in yesterday for the opening of Sugar Ray Leonard's training camp at Sheraton Inn-Washington Northeast they saw that the challenger had to be stopped from beating up on a sparring partner wearing a T-shirt inscribed, "Champ."

It was 6-foot-1 Aaron Caldwell, 22-year-old Washington amateur welter-weight, who was engaged because "he is strong like Duran and has the good leverage in delivering a punch that makes Duran a strong hitter." Caldwell has lost only three of 52 bouts with 45 knockouts.

Leonard said afterward that he has planned a whole new concept in his selection of sparmates.

"They are not dirty fighters," Leonard said. "They have different techniques from those I had for the first bout with Duran. Dale Staley just doesn't believe in rules."

Staley, 23, is a professional from Forestville, Md., with a 15-3-1 record and 11 knockouts. In one bout his opponent accused Staley of biting.

Is Leonard expecting Duran to engage in brawling tactics again when they meet in New Orleans on Nov. 25?

"He comes in to fight; I'm envisioning a completely different bout for myself. I'll give him a mixture. What I want are sparring partners throwing overhand rights, right-hand leads, and body shots (as Duran did last time)."

Leonard appeared to get his sports mixed up once, at the start of the third round in his session with Caldwell. The former champion was closing in with his left glove well below his hip when he unloaded a left hook that looked more like a football lineman's forearm shiver.

Leonard leaped in with a clubbing left hook to the body, stepped back to give Caldwell a chance to recover some poise, snapped his head back with a full arm's length jab to the nose and followed up with a crushing right uppercut to the heart.

Leonard backed into a corner, as if Duran were closing in on him, lashed out with a repid right cross to the jaw, and spun out of the corner with a furious flurry of punches that left Caldwell gasping. The action was held up to spare Caldwell. When the sparring resumed, Leonard uncorked another buzz-saw combination and a jarring right lead before the bell.

Leonard was doing the damage with 14-ounce "pillows," or training gloves, and boxing four-minute rounds instead of the standard three. He took 45-second rests instead of the rugular full minute.

When beefy Staley came on for his test of wills, Leonard encouraged him to try to score with right leads and potshots with either hand. Near the end of the second of his three rounds against Leonard, Staley abruptly was crowded, took a heavy pummeling, and was rocked by a left hook to the head before the bell.

Leonard's attorney, Mike Trainer, said his client "will not get caught up in the hype for the bout this time, because he has a guarantee instead of working on percentage. Neither boxer will receive as much as Leonard did last time ($10 million) but their combined purses will set an all-time record." l

Leonard is going to New Orleans today for a press conference for the Duran fight and will be in New York Friday to be a commentator on the cable (Home Box Office) telecast of the Gerry Cooney-Ron Lyle heavyweight bout on Friday at the Nassau Coliseum in Long Island, N.Y.

"After that there will be nothing else to break my concentration from Nov. 1 to the night of the fight," said Leonard, noting that he will finish his training in New Orleans, beginning about Nov. 11.