I love how the thread turned from announcement of new VEX IQ plastic parts into the discussion of anodized aluminum in a matter of a few posts!
If you google how to test if aluminum is anodized, you will learn that the simplest method is to use multi-meter to test for conductivity.
Aluminum oxide is a good insulator and if process of anodizing makes a thick layer of oxide - that will create very large electric resistance.
I used several different VEX aluminum parts for the conductivity test.
On top is a really old 5-wide c-channel piece that is, probably, 10 years old. VEX must have changed manufacturing process process and likely the type of material. You can see that it has more rounded holes and darker color.
Below it is a piece of 2-wide c-channel that had seen a lot of beating during the last few seasons.
And on the bottom is a new 3-wide that was recently pulled from the sealed package.
Also, there are two standoffs: an old 6" that had seen better times and a new 5" that was just unsealed.
I tested conductivity in several ways: by gently touching surfaces with the round sides of the probes, by forcing round sides of the probes into corners of the square holes (pictured) and, finally, by pushing into surface with the sharp pointy tips of the probes and further scratching if necessary.
The old 5-wide piece, as well as both standoffs, had the resistance (both on the flat surface and in the holes) on the order of single to double digit ohms if you just gently push the probes and then leave them laying under their own weight.
After some light scratching the resistance would instantly drop to <0.1Ω, which indicates to me that those parts must be only protected by the very thin layer of naturally formed aluminum oxide.
The 2-wide and 3-wide, however, had different measurements.
If you gently touch their surface with the round side of the probes they were giving resistance beyond 20 MΩ range of this meter.
The flat surface would read <0.1Ω only after extensive scratching with the sharp tip.
The deeply scarred parts of the 2-wide, however, would drop to a single digit ohms as soon as you push the pointy tip of the probe with very little force (down to zero with very little additional force).
Another interesting data point was that compared to flat surfaces, it required very little force on the long edge (where c-channels are cut from each other) and inside the square holes (where the metal is stamped out) to drop resistance to Mega-ohm range and beyond.
My best guess is that source aluminum sheets for the new c-channels come well anodized and, after they are stamped, cut, and bent the second round of anodizing is much shorter or done with different process that creates much thinner and weaker protective layer.