I found out they are making the last Hunger Games book into two movies. This definatly shouldn't be happening. I can understand HarrPotter since there's nothing you can cut really but you could probably fit Mockingjay into a 2 2 and 1/2 hour movie.
I have to think the suit will get post production effects. That thing looks way too drab not to mention it looks like a rubber suit.
It's most likely a pre production suit since this was the first day of shooting. You might see a couple more like this before they get the right one for the actor. The helmet does look like Dredd's helmet.