I have only seen one Model 10 up close and it was blued. It was about 1.5 years ago. $425 Chicago PD officers duty weapon being sold to close out estate. 1968 10-6 with 6" barrel and a little corrosion. I wanted it for $385 back then. It sold to someone else for the $425. My loss. OH and by the way, make sure it is Stamped N on the frame and some of the parts for Nickel....I believe they did that in various locations on the weapon POST war. Should be stamped under grips near bottom of frame and maybe on cylinder as well, etc.
I know RN meant re-nickeled at the factory.