GANDER MOUNTAIN <GNDR.O> BUYS WESTERN WEAR FIRM Gander Mountain Inc said it acquired privately held Western Ranchman Outfitters, a Cheyenne, Wyo., retailer and catalog seller of western apparel. Terms were not disclosed. Western Ranchman had sales of about 2.2 mln dlrs for the year ended Jan 31, 1987, the company said. Gander Mountain sells brand name hunting, fishing and outdoor gear through catalogs.