The ornamental design for showcase frame component, as shown and described.
FIG. 1 is a top and right side perspective view of the showcase frame component, shown at an enlarged scale and shown with the middle section removed, solely for the purpose of fitting the enlarged view on the page;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a bottom and left side perspective view of the showcase frame component shown of FIG. 1; and,
FIG. 9 is a top and left side perspective view thereof.
The broken lines are for the purposes of illustrating the environment of the article only and form no part of the claimed design.