UPDATE:
Finally started painting & weathering some of the pieces. Both boots and ankles are done! First, I laid down a coat of silver, then coated with Rustoleum Earthy Green. After the green was dry, I used a small piece of 80-grit sandpaper to scuff it up, revealing the silver underneath (I may have gone a little heavy on the damage, but I will adjust when I do the rest of the pieces. If anything is gonna be more beat up, it would likely be the boots anyway). Used black and brown oil paints, thinned with paint thinner, for the wash. This was the first time I've used oil-based paints, instead of acrylic. I like the results a little better. The oil paints seem to "gunk up" a little better than the acrylic.
I have the shins painted, but haven't done any weathering on them yet. You can see the difference. I knew the weathering would darken it up a bit, so I went with a slightly lighter green. It's not an exact match (still more grayish-green, instead of the slightly yellowish-green from the games). Still, I'm really happy with the final shade I was able to get.