The town is seeking information about the wooden Olmsted Historic District sign that stood near Paradise and Walker roads. The sign was seen on the ground on Oct. 29, the day Hurricane Sandy reached Massachusetts, but before the winds picked up, and has not been seen since. “We don’t know what knocked it down; we just know it was down,” said town planner Peter Kane, who said there was no evidence of an automobile accident and no tree limbs down at that location. The sign is one of two for the district, an early subdivision designed in 1988 by famed landscape architect Frederick Law Olmsted, who also designed Boston’s Emerald Necklace and Central Park in New York City. Anyone who has the sign or has knowledge of its whereabouts is asked to contact Kane at 781-596-8829or firstname.lastname@example.org.