Regardless of whether it was new or second hand it still would have been traded in as that is how CEX works. Everything they sell new or second hand has been traded in for cash or exchange. That's a pretty good price for a pro controller whether its new or second hand though. I got mine bundled with the Zombie U Premium Deluxe Wii U console.
oh,didn't realise that, I assumed mine was new coz it still had the club Nintendo points card in it unused. Which was nice.