One of the famous slope dark streaks on Mars might be visible in a 3-D Hirise image of Gusev.
Here's a cropped image showing the feature:

Taken from:

Another image shows Spirit was close to the area where the dark streak appears when it was at West Spur. However, there is a smaller hill that might have blocked view of the streak when it was at West Spur:

"An inner basin among the Columbia Hills may contain the layered deposits Spirit has been seeking. Spirit should reach the spot named West Spur by June 1. The rover will most likely remain there for about a week to study outcrops and rocks in the area...."

Taken from:

New views of Mars
Rover scientists begin to unravel the geological mysteries of the martian landing sites.
Andrew Fazekas
May 25, 2004
http://www.astronomy.com/asy/default.aspx?c=a&id=2064

Spirit now however is further away, near Home Plate.

Bob Clark