Yet again, I'm fairly certain this was an older drawing. It's still a nice drawing. It just pales in comparison to your modern stuff. It really does seem to be from a different artist. I guess you were just experimenting back then. It looks kind of silvery.
It's probably just a shiny metal. I like the little guns sticking out. I just now notice the screws. Even your early stuff is above average. Then again, most of the stuff I review is just plain good.