Thats an excellent price considering the accessories if its in good shape. I wouldn’t bother haggling over it.
Its high mileage but its pretty safe to say that its all highway miles and the bike was used for long distance touring, which isn’t really bad at all. Just drill him about whether or not he used motorcycle specific oil when doing his oil changes. Ask for maintenance records if you can. And you may find yourself having to replace the voltage regulator/rectifier which is about a $100 part but its easy to replace, can do it yourself with a screwdriver.