I wouldn't consider it on a M21, but it brings up a good point; case coloring is yet another attribute that fell by the wayside as guns became more 'advanced'. If I were in 1935 buying a big-buck gun, such as a M21, I'd be pretty disappointed in a blued finish. I still would be today. A blued receiver screams "corporate cost cutting measure" to me. Is there any other high-end shotgun that gets shipped with a blued receiver?