Samsung SM-T337A Rear Facing Camera Casing cover

The rear facing camera of a recently acquired Samsung Galaxy Tab 4 SM-T337A has a smoky haze to the picture image. Originally I replaced the rear-facing camera, and then determined that the external camera cover on the rear of the plastic case body is actually causing the cloudy images. Without the rear case body the camera takes great images. Is the rear camera lens cover glass or plastic? Can I polish it with fine (2,000-grit+) polish or such? Other options are to replace that piece (it is an insert in the case body) but parts are not easily available. Thoughts?