The ornamental design for the writing instrument component, as shown and described.
FIG. 1 is a side elevational view of a first embodiment of a writing instrument component shown with dashed shading to indicate the color silver and cross-hatching to indicate a darker contrasting color compared to the other surfaces therein, the other side views being identical;
FIG. 2 is a perspective view thereof shown with dashed shading to indicate the color silver and cross-hatching to indicate a darker contrasting color compared to the other surfaces therein;
FIG. 3 is a top plan view of a second embodiment of a writing instrument component; and,
FIG. 4 is a side elevational view of the second embodiment, the other side views being identical.