If at times The Pajama Game seems less like a musical than a play interlarded with a revue, Seattle Musical Theatre’s production does pretty well by those revue numbers, making it clear why the show’s revered (if not quite making a case for it being revived more often). Though it’s indisputably one of the canon of musicals that made the ’40s and ’50s the golden age of the genre, The Pajama Game is wildly uneven. In Richard Adler and Jerry Ross’ score, gems alternate with duds. A fantastic premise (labor and management fall in love during contract negotiations at a pajama factory) is tainted by some dumbfounding clumsinesses. Still, the show has its pleasures. Bob Fosse’s earliest signature number, “Steam Heat,” is delivered with relish by Lindsey Larson, a copper-haired tootsie who plays round-heeled secretary Gladys something in the style of early Anita Gillette. And there’s this stroke of genius: How did anyone ever think of writing a love duet at the tempo of the William Tell overture? “There Once Was a Man,” which uniquely captures new love’s jumpy giddiness, is a galloping showpiece for leads who can handle it, and Kirsten deLohr Helland, as grievance-committee head Babe, and Derek Hanson, as abrasive but irresistible new factory supervisor Sid, put all their energy into it and score big. Helland takes Babe beyond perkiness to a sort of straight-spined, stage-owning super-competence, and Hanson is most convincing as a romantic; his ballad “Hey There–the first verse sung into his Dictaphone, the second a duet with his recorded self–is his peak moment. GAVIN BORCHERT

Fridays-Sundays; Thu., Sept. 29, 7:30 p.m. Starts: Sept. 9. Continues through Oct. 2, 2011