Parashooter wrote on Apr 19^th, 2016 at 7:44pm:

Not so, Paul. Modern factory centerfire brass cases are annealed several times during manufacture and normally receive a final neck/shoulder anneal that would show colors if it weren't polished off during a final tumbling operation before loading. U.S. manufacturers ordinarily perform this final polish on their commercial cases (military specs require the color to be visible, so this step is omitted for GI contracts).

I did not know that Para.  Good to know though...  Thanks Para.