Don’t be fooled by the leopard pencil skirts and Joan Holloway–style lingerie lining the walls at rockabilly boutique SlapBack (490 Metropolitan Ave., nr. Rodney St., Williamsburg; 347-227-7133), opening February 1. Aside from fifties-era décor and doo-wop humming on the stereo, nothing in the 680-square-foot women’s shop is authentic vintage. Rather, owner Renee DiDio, a ruffle-hem-rocking former retail director of the fitness chain Flywheel, stocks contemporary brands that marry sultry throwback silhouettes with modern fabrics and sizing. The selection covers established retro-reproduction labels, such as a stretch-denim shirtdress from Unique Vintage ($158) and a cherry-red tapered sheath from Bettie Page ($128), as well as pinup-style bras and panties by Greenpoint’s Dirty Dolls (from $22) and a vast supply of tights, fishnets, and back-seamed nylons (starting at $8).