Why not take it apart, polish it and reassemble ?

It wasn't bad taking it out.

 

Maybe the lens is 'plastic-welded' to the cluster kind of the same way the door pulls are to the door panels. Whether to save cost of a few screws or it keeps the internals cleaner since it's sealed, hard to say. Maybe I'll venture a trip to my Chevy dealer, back up to the parts counter and see what they run.