It's about a year and a half old. It has a moderate patina, it shows a little wear on the handle and the piping, but that's it. I don't know what price would be fair. Should I send it to mypoupette and get a certificate of authenticity before selling it? Just to give the buyer piece of mind? I purchased it myself at Saks so I'm confident it's authentic, but I just want to know what extra measures I should take.