One of the items I addressed on my GSG was an overly thick firing pin nose. When I first got it I though the firing pin seemed a bit broad and so as part of my on-going work to refine the GSG to perfection I carefully stoned the pin to narrow its nose down to the same thickness as other .22's I own.
Then I got around to ordering another firing pin as part of creating a supply of "spares" and discovered the replacement firing pin's nose is the same width as my original--as delivered! The new pin also shows a distinct bluish color indicating hardening and tempering.
I don't know if this reflects indifferent quality control or perhaps an on-going process of product improvement but I'm impressed.