[plnyyanks]

You'll be more likely to obtain used boulders than the defenses, I think.

The defenses all get shipped back to FIRST (although you can contact HQ and see what they're doing with them - it can't hurt to ask). I think the districts have only a few weeks (?) before FIRST is expecting the game specifics back, unless they've agreed to keep a set for offseason events, so you may have some luck if you move quickly.

At regionals, they were instructed to keep used game pieces with the truck for the season. Which means there were all given away in St. Louis or headed back to New Hampshire now. I don't know of any specific instructions given to districts regarding their game pieces, you might have some luck following up on Tim's lead.