As derivative movies go, "The Sting II" makes a diverting, inoffensive case for itself.

The director, Jeremy Paul Kagan, seems to have emerged from his first significant credit, "The Chosen," with enthusiasm and confidence to burn. This new-found assurance pays at least incidental dividends in "The Sting II," opening today at area theaters.

You can share Kagan's obvious pleasure in the period setting--a Runyonesque New York, circa 1940, faked for the most part in California--and an adroit, humorous ensemble of players, led by actress Teri Garr in the role of a con artist enlisted by the larcenous heroes, who engineer an elaborate new scheme to "sting" a mobster nemesis. David S. Ward's screenplay may suffer from one's recognition of the same methodical setup as the original, unfolding with minor double-crossing reversals and surprises, but Kagan sustains enough momentum, gratuitous comic distraction and pictorial gloss to prevent the material from nodding off on automatic pilot.

Ward's follow-up remained on hold for several years, awaiting the approval and/or availability of Paul Newman and Robert Redford, who ultimately decided not to press their luck, so there may be the better part of a new moviegoing generation available to "The Sting II." If you never saw the original or recall it only vaguely, the recycled tricks might come as a perfectly satisfying novelty. One of the casting replacements--Jackie Gleason for Newman--can also be enjoyed up to a point for sheer effrontery and an irresistible element of inside joking, playfully reinforced by a sequence in which Gleason as the veteran con man Fargo (formerly Henry) Gondorff hustles his mark (Karl Malden as an excitable hood named Macalinski) in a game of pool.

Gleason is clearly a debonair shadow of his once imposing comic self. The years have cost him the robust, dynamic attributes of his overweight prime as a funnyman, but at least the role of Gondorff offers the dignity of a droll elder statesmanship, a considerable improvement over the inert indignity of his assignment in "The Toy." Perhaps it's no longer realistic to anticipate anything strenuously or wildly funny from Gleason, whose gallery of TV characters inspired compulsive imitation in the schoolboys of my generation, but Ward and Kagan have retailored Gondorff for fastidious Old Smoothie touches that flatter and protect their star.

Regrettably, their luck and ingenuity break down drastically with the other major replacement, Mac Davis for Redford as Gondorff's prote'ge' Jake Hooker. For some reason the vitality and humor that Davis projected as the quarterback in "North Dallas Forty" have vanished in the interim. Davis looks ill at ease and out of sorts. His droopy, listless presence also puts a crimp in Garr's style, since her character is supposed to be romantically as well as professionally entangled with Jake. It's impossible to think of them as equals on any terms. While finally cast as a woman who's nobody's fool or patsy, Garr is nevertheless stuck with an inexplicable sad sack of a leading man.

Although it's never intended to throw a pall over the exposition, "The Sting II" is set in motion by a death in the fraternal family to which the heroes belong. Oliver Reed assumes the role played by the late Robert Shaw, the mobster Doyle Lonnegan, but having been the original victim of the sting, Lonnegan is no longer appropriate as the sucker. On the contrary, he contemplates getting even by setting a trap for Gondorff and Hooker. The sting-within-the-sting format allows the tricks that couldn't be played on Lonnegan twice in a row to be played on Macalinski instead. Naturally, the heroes still prove farsighted and slippery enough to counter-sting Lonnegan just when he thinks he's got them set up for the kill.

There's an arguable tactical error in this new arrangement, which places a premium on broad comic touches at the expense of a persuasive menace. Karl Malden seems too much the bluff buffoon to pose a serious threat to the Gondorff-Hooker troupe. He becomes the butt of slapstick humiliations rather than the surgically manipulated needle applied to the Shaw character by Newman. Lonnegan undergoes a facetious transformation at the same time, becoming a suave, smug backstage manipulator who trades vaudeville patter with an ethnic underling, Jose Perez, doing Puerto Rican dialect shtick that seems roughly a generation premature.

Ron Rifkin, as Jake's partner Eddie, is the steadiest of the supporting actors, and Max Wright contributes a superb bit as a department store floor manager obliged to settle a battle of skills when Garr and Davis, borrowing a leaf from the lovers in Lubitsch's "Trouble in Paradise," become acquainted by planting stolen merchandise on each other. "The Sting II" tries to keep moviegoers similarly off balance with a secondhand caper script, but the attempt seems amiable enough to compensate for the redundancy of the material.