Richard your parts look great and finish match very well to what I have gotten we may have the same media 3/16"x3/8" ? I didn't think pics would show true color but yours show sheen, color, and finish well.
With the original control arms and essentially any of the stamped steel components that are now 50 years old, they all developed at least some rust early on and more often than not, pitting occurred over the surfaces of these parts. It can be difficult to restore them to the original appearances of "New Stamped Metal". I hear rumors that somebody has begun a reasonable close reproduction of these now, but they get painted.
Regarding the original ones I have, Charles did the tumbling for me a couple years ago now. He can point out whatever media he used if he chooses but I am sure there have been several threads in past years on what restorers have been using (search feature is your friend).
I used Rust 911's "Metal Shield 2009" (though I am no longer seeing it available at the Rust911 site) to coat the arms (similar to Boeshield T9) and it gave the parts a light sheen initially that has since reduced some in sheen.
Below is a picture of the upper arm with Moog Upper ball joint and NOS boots aged 1 year. This is what I ended up with as a "finish" and I am satisfied, not the typical monotone look like the first picture in this thread.
