The ornamental design for a rearfender for an armored vehicle, as shown and described.
FIG. 1 is front perspective view of a rear fender for an armored vehicle of my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top plan view thereof; and,
FIG. 5 is a right side view thereof.
The dash dot dot lines immediately adjacent to the claimed areas in the views represent the boundaries of the design. The dotted lines in the figures illustrate the portions of the design that form no part of the claim. None of the broken lines form any part of the claimed design.