K98k bayonet lugs left in the white?

I've seen a few k98k over my lifetime, where the bayonet lugs were left in the white and not blued. When did the transition of bluing the bayonet lugs happen? Pre war? Early war? Mid war?

I prefer the look of the lugs being left in the white myself. I'm considering buying a bayonet lug that's in the white and putting it on my RC k98. Is swapping out the lug as simple as removing the pin that's holding it in place or is there more to it?

Thanks!!!

As I recall...it is a tight fit.....is there anything wrong with the one that's on it(except being blue)?