This morning, a who’s who of New York City and beyond flocked to the Metropolitan Museum of Art to preview the Costume Institute’s latest blockbuster, “Costume Art,” a sweeping show that explores the significance of the dressed human form in fashion and fine art. As the introductory wall text reads, “Clothing does not simply cover. It mediates identity and articulated hierarchies of class, gender, belief, belonging, and difference.” But while the crux of the exhibition (and Vogue’s pre-gala fiesta on Friday) may be bodies, bodies, bodies, architecture buffs will find equal inspiration from buildings, buildings, buildings. Today’s unveiling marked the debut of the new 12,000-square-foot Condé M. Nast Galleries, named for Architectural Digest’s parent company founder and designed by the ace architecture firm Peterson Rich Office (PRO) at the intersection of historic edifices. Architecture firm PRO, led by the married couple Miriam Peterson and Nathan Rich, designed the new Condé M. Nast Galleries at the Met.…