I must admit you're most probably right, and my eyes fooled me, haha... However, I'm not completely certain of this.
I thought there might be some kind of liquid because:
1. It looks like it.
2. The surfaces are all in some kind of canals (I guess something may have been flowing there once)
3. The rocks near the surfaces all seem to have eroded: more near the bottom than at the top, like something has been flowing there.
4. On other images, like this one from sol 110, the seemingly reflective surfaces are completely lacking, and you can clearly see what plain sand looks like: it has more texture.
I've been trying to find more clues.
Like: the shadows in this image are pointing left to right (see the rock on the left), while the "shadows" in the areas I'm referring to are clearly top to bottom. But I'm not too sure about that.
And: there seems to be a "riple" in the presumed liquid on this picture making the pond-effect even more dramatic. However, on the image which was taken a 24 seconds before this one, the riple is exactly the same: sand.
So... for now have to agree with you.
At this moment, I'm also wondering, what are these two giant pinnacles that seem to have broken off from something and which have a weird texture. Does any of you know? Link: http://mars.jpl.nasa.gov/msl-raw-images/msss/00109/mcam/0109ML0684009000E1_DXXX.jpg