2016 Championships SE autographed gaming chair

Looking for advice or interested buyers. I have a friend trying to sell a special edition Maxnomic gaming chair from the 2016 LoL Championships autographed by the players in the championship. Never used. Fantastic looking logos embroidered front and back. As far as I know only a handful exist – have never seen another listed anywhere. Will provide documentation detailing where he got the chair from for provenance. Chair alone sells for $400, but he has no idea what it’s worth. I am thinking its close to $800. If you’re interested in buying, it’s located in north central Illinois. What’s it worth?