Abstract: A headed fastener clip having a threaded shank with a T-head embedment molded in a hex nut head for rotatably threading the clip into a support. A trim piece attachment post protrudes oppositely from the shank. A pair of spring arms are cantilevered from the post outer free end and diverge dependently therefrom to free ends spaced closely above the nut head. A catch portion adjacent each arm free end dimensioned to overlaps in use mutually opposed marginal edges of a fastener-receiving opening in the trim piece. The nut head has platforms on the head that underlie and support the opening marginal edge when the trim piece is installed on the clip. The fastener clip is first threaded into the support, the trim piece fastener opening registered with clip head and then the trim piece is pushed toward the support.