Nope, MI is monochrome
The plan is to get color context images using the Pancam of sites imaged by the Microscopic Imager. There was a reference in the technical paper about "coregistering" Pancam color images with the MI, presumably to overlay color information on MI images. The color info will be at a much lower relative resolution, so we probably won't be able to make out the red band around the circumference of the spheres (ref. Arthur C. Clarke's "Rama" novels).