A cover plate for an instrument panel carrying a captured fastener adapted to be assembled to an underlying instrument panel support structure by a closely overlying and sliding motion of the cover plate relative to the support structure. The cover plate has a thickened boss portion formed with an internally threaded passage. The fastener has an elongated shank extending axially to the passage and includes an unthreaded mid-portion and a threaded outer end portion, terminating in a tip. A pre-assembly position of the fastener is attained by rotation of the fastener with respect to the boss's threaded portion just sufficent for supporting the fastener but not enough to advance the tip from within the boss thereby preventing the tip from projecting out from the surface of the cover plate. An assembled position or advanced position is attained by further rotating the fastener causing its threaded portion to engage the underlying instrument panel structure and leave the fastener's unthreaded mid-portion totally within the boss, free of any threaded engagement while the threaded end portion engages a C-clip supported on the instrument panel.