Stargate Props, formed as an offshoot of Legends Memorabilia, sells items on behalf of MGM that are guaranteed authentic. I've done business with them and found them to be friendly and staffed by fellow sci fi fans. Their website is http://www.stargateprops.com/ They offer auctions on eBay several times a year and conducted a very successful set of auctions that raised much needed funds for local foodbanks.