Cleat structures, e.g., for golf shoes, may include a flat and flexible interior surface and/or a generally disk-shaped perimeter area that includes features to promote in-molding of the cleat to a footwear sole component (e.g., to permanently engage the cleat with an outsole member). Such cleats may provide a flexible and comfortable base, including a low profile, e.g., to enable formation relatively thin and/or flexible footwear sole components. Footwear sole components and articles of footwear that include one or more in-molded cleat structures of this type also are described. Molds used for in-molding procedures and methods of using the molds to make articles with in-molded components (e.g., for making footwear sole structures including one or more in-molded cleats) also are described.