I'm pretty sure its plated then dirtied.
I think you're right that they plate it first, but what I'm trying to say is that I don't think the pre-weathered version would look like a pristine "throne room" C-3PO finish.
You can't get that effect otherwise. I also saw the clean versions by Barton before they were dirtied up. Lucas wanted them dirty.
My theory was that given how Sideshow's factories have been performing, they realized that it would be difficult to get a pristine finish (especially on C-3PO), so they decided to weather them. Just look at how much trouble people are having getting good paint jobs on the 1:1 Iron Man bust -- and that should be simple compared to an entire droid. They also probably wanted to separate themselves from the Don Post versions. Do you know for sure that Lucas dictated the weathered finish? I personally prefer it, so I'm not complaining.
Is there additional pictures from the SDCC? link?
There are some good pictures in this
link from the Rebelscum forums. It was actually these pictures that convinced me that they would be worth getting, since the ones on Sideshow's site aren't really that great. No one on any of the sites I frequent has gotten a C-3PO yet, so these are the closest thing we have to in-hand photos of him. A couple of people on Rebelscum have gotten R2 units, though.
Damn, those are both just unbelievable! So from the site it looks like C-3PO's arms move... any idea how much, or if he has any other points of articulation?
C-3PO's head turns, his arms move at the shoulders, and the hands turn at the wrists. R2's dome spins around. And of course they have lights and sounds.
Does anyone have the don post droids? I heard these are better (there were some casting problems with the Don post ones - especially on r2).
There is a
thread on the Rebelscum forums about the supposed accuracy problems with the droids, and there are some pictures there of the Don Post versions of the droids. As replicas of the movie props, the Don Post versions may be more accurate, but as you say there are some problems as well. The C-3PO is a bit undersized, and the R2 is apparently kind of flimsy and for some reason has a clear "eye" where it should be black. In any case, they are hard to come by nowadays, and would likely be at least as expensive as the Sideshow versions.