I reporoduce below an article from the Nikon website of 16 Dec 2014.
We have confirmed that there are cases in which D800E digital SLR cameras were received for repair, only to find that the cameras were actually fraudulently modified D800 cameras whose covers had been replaced with D800E covers. It seems that these fraudulently modified products are in circulation via Internet auctions and the like. As the Nikon warranty does not apply to fraudulently modified products, Nikon will not inspect or repair such products. In addition, Nikon cannot be held responsible in any way regarding the use of fraudulently modified products. Please take all necessary precautions to ensure the authenticity of a camera before purchasing one.
Identifying these fraudulently modified cameras
Display an image captured with your camera in the camera monitor. When the overview* display option is enabled in full-frame playback mode, the name of the camera used to capture the image is displayed in the top right corner. If "NIKON D800E" is displayed, your camera is an authentic D800E. If any other name is displayed, your camera is a fraudulent D800E.
We have confirmed that there are cases in which D800E digital SLR cameras were received for repair, only to find that the cameras were actually fraudulently modified D800 cameras whose covers had been replaced with D800E covers. It seems that these fraudulently modified products are in circulation via Internet auctions and the like. As the Nikon warranty does not apply to fraudulently modified products, Nikon will not inspect or repair such products. In addition, Nikon cannot be held responsible in any way regarding the use of fraudulently modified products. Please take all necessary precautions to ensure the authenticity of a camera before purchasing one.
Identifying these fraudulently modified cameras
Display an image captured with your camera in the camera monitor. When the overview* display option is enabled in full-frame playback mode, the name of the camera used to capture the image is displayed in the top right corner. If "NIKON D800E" is displayed, your camera is an authentic D800E. If any other name is displayed, your camera is a fraudulent D800E.