Billingsley Co. has closed on its purchase of the Landmark I and II office buildings in northwest Dallas, the company announced. The purchase was made via a partnership between Billingsley and Stockbridge Real Estate. The seller, Behringer Harvard, has kept an economic interest. The buildings will be renamed Gramercy Center North and South, according to a press release. “This investment represents well-located, quality assets in one of the strongest submarkets in Dallas.