Finish of gear shift lever on a 33

[Doctor's Ford]

My shift lever had surface rust. I cleaned it with fine sandpaper and was shiny for a short time. Now it has again developed a significant surface rust and some pitting. Sanded again and is looking pretty once more. What is the correct finish I need to apply to protect it? Is it chrome and then sand it lightly to a butler finish like the hand brake handle? If possible I want to reproduce the original finish. Appreciate any suggestions. Thank you