I would think you can paint the tube shields. But it's not a must.
For my Mainline i found a pair of exactly the same tube shields in black via an online seller (eb*y).
I was thinking a metallic flake green, but you tangentially answered the question behind my question, which was "will the heat from the tubes peel the paint from the shields?", which seems to be the case. I'll look for some anodized ones. Thanks!
I have had success powder coating tube shields in the past and not having the heat bake it off. I don't think the 6922 tubes will get hot enough to peel your paint off, but its really hard to say with absolute certainty. If you wanted to do something like this in a Mainline, I would be more confident that your paint would fail.
Ok, got it. It doesn't seem like I have much to lose just giving it a shot since the shields aren't too pricey if the paint does flake.
I haven't found anyone around here (St. Louis, MO area) who will do reasonably priced powder coating. I think the company that I checked into for my SEX chassis and bell wanted $175 to do a flat white. I would have loved to have gone that route instead of spray painting.
I've painted the shields on my Seduction and Reduction phono amps (black or flat black) with great results - the paint hasn't come off after years of use and even leaving them on for extended periods of time. Nothing magic about the process; make sure the shields are clean prior to painting, follow label instructions, and enjoy.