Site Help ID Your Mac
In a different tab or window, go to Apple's Online Check Coverage (https://checkcoverage.apple.com) and enter your serial number (etched onto lower case). What information is displayed below the picture?
MacBook Pro (Retina, 15-inch, Mid 2012)
MacBook Pro (Retina, 15-inch, Early 2013)
MacBook Pro (Retina, 15-inch, Late 2013)
MacBook Pro (Retina, 15-inch, Mid 2014)
MacBook Pro (Retina, 15-inch, Mid 2015)