Help! I am in love, love with these GUCCI rain boots that are for sale on eBay.com. http://cgi.ebay.com/NIB-GUCCI-rain-flat-boots-BLACK-GG-rubber-size-37-7-5B_W0QQitemZ130183080040QQihZ003QQcategoryZ63889QQssPageNameZWDVWQQrdZ1QQcmdZViewItem First, I don't know if they are authentic. The seller has very good feedback. Second, do Gucci shoes run true to size or do you have to go a size up or two? HELP!