Was trying to answer the original post, if you're doing a car to be judged competitively you probably want/should to send ALL the brushed aluminum pieces out so they match and look as correct as possible. There are a number of places that do this. I did send the "chromed" plastic pieces out to be redone, I used Tony's Auto Classics (http://www.tonysautoclassics.com/
) he also does the aluminum inserts too but I did the inserts myself as my pockets are not that deep and my car is not a trailer queen, it gets driven and I hope to do that today.
Even if you are not competing I think just doing one piece will be a bit challenging to do and have it match the un-restored pieces, age = patina.
I'm not sure what the solvent took off - 40 years of grime and the adhesive from old dash plaques? I did NOT use any sandpaper - only steel wool and Scotch brite - slow, careful, with the "grain" and only enough to freshen them up as they were not bad, more of a deep cleaning, and then cleared them.
The door pieces on my car were too deeply scratched so I got reproductions from Burton (http://www.burtonantiqueautoparts.com
) as I felt his were the best (at the time - maybe some one else makes better now) and I'm pleased with them and Mr. Burton was very good to deal with.
Yes , there is a slight difference between the "color" of the Burton door inserts and the pieces I did but I have to point it out. Hope this helps.