The ornamental design for exterior rear panels for an automobile, as shown and described.
FIG. 1 is a perspective view of exterior rear panels for an automobile embodying the invention; and,
FIG. 2 is a rear view of the design shown in FIG. 1.
The broken line showing of the environment is for illustrative purposes only and forms no part of the claimed design. The top, sides, front, and bottom views are not part of the claimed design. The portions of the design shown in solid lines are constructed of wood or a material conveying the ornamental appearance of wood. The automobile to which the exterior rear panels are applied in the illustrated embodiment is a Chrysler PT Cruiser.