Will someone with blindness due to injury also have eye discoloration?

Usually No: Certainly if the eye was directly affected, injured and scarred it may appear different. But, if the eye injury was due to a retinal detachment or optic nerve damage, the eye externally will appear completely normal.

Eye injury: Yes, possibly depending on the nature of the eye injury. Eyes that don't see and function may shrink, may become calcified, may turn painful, and some times , may need to be removed. Also, the pupil may lose it's normally black appearance and turn white from a dense cataract. The iris may also turn different color if damaged.