Wow, you're way more organized than me. I just dump all the bits in a bucket.
Cold blueing or any blueing for that matter only works on carbon steel. That gizmo you have there is 410 stainless so blueing won't take on that. Your choices are an applied coating (spray paint), plated finish (hard chrome or nickel), or a form of case hardening known as salt bath nitriding (melonite, isonite, tenifer, nitron et. al.), or black oxide finish (a chemical/acid dip similar to bluing but for stainless alloys).
I'm probably gonna send mine off for nitriding once I'm done fiddling with the fiddly bits.
For what it's worth, nitriding is not a coating. It is a case hardening process wherein the steel parts are immersed in a bath of molten cyanide salts through which nitrogen gas is bubbled. The finished part is left with a supremely hard satin black surface layer.
Then again, there's nothing wrong with leaving it alone or perhaps freshen up the finish with a mixed media blast. The secret sauce for replicating the factory finish is this stuff here...
McMaster-Carr
50 psi is where I run my cabinet.
For blasting you'll want to fashion a cork of sorts to protect the front face and inside bore of the barrel bushing from the abrasive media.
Cheers
Bill