Any updates on how well their coating lasted? I ordered two new mag release buttons for my daily carry's (CW45 and PM45... not at the same time) because they were starting to rust (summertime AIWB carry, working outside in 90+ degree humid weather). I could reblue them, but thought your suggestion might be more resiliant.
The most siginificant area of rust for me is the serrated section your thumb presses to release the magazine. For now I just let oil sit on it for a few minutes and wipe away most of it once per week.