Well, I'm currently re-reading the Usopp vs. Luffy fight because I'm bored, and I had a thought- could Usopp have picked up a Reject Dial from Skypiea?
I know they're rare and the Skypieans probably wouldn't want to part with them, but remember they had no need to bear arms, plus Skypiea didn't have rubber so they must have thought it was a fair trade.
Thoughts?