The cozy, old-world atmosphere of Bobo, a town house restaurant in the West Village, was a fitting setting for Vera Wang's first-ever runway show for her lower-priced Lavender Label collection. There was more than a hint of the fifties and sixties in a nubby tweed skirtsuit with a fur shawl collar, a satin-front/knit-back skimmy belted sheath, and a cable-knit cardigan that topped a brocade blouse and a narrow three-quarter-length skirt. Antique pearl necklaces, gamine berets, and long braids added to the classic, almost retro mood of the clothes, whichif not bursting with new ideaswere appealing and pretty. The most modern-looking pieces took cues from the designer's signature collection. A long silk dress with a panel of net and paillettes down its front is a Wang trademark, as is the soft, togalike appeal of a gathered-waist gown that dipped low in the back to reveal a sexy swath of shoulder.