Here is the exact notice, and as HR photography said it doesn't always fix the problem. Don Kuykendall: Nothing is going to fix the resell value! The resolution of the problem being the D610 introduced before the D600 was even 1 yr old was the death of the D600 value FOREVER.
From Nikon:
Dear Timothy,
Nikon Inc. is contacting you regarding your D600 D-SLR camera, serial number 30xxxxx. As you may be aware, Nikon Inc. recently issued a Technical Service Advisory regarding the Nikon D600 D-SLR camera. This Advisory related that some users of Nikon’s D600 D-SLR camera have reported the appearance of tiny spots on certain of their images. Not all users have experienced this issue. Nikon has thoroughly evaluated these reports and has determined that these spots are caused by dust particles which may become visible when the camera is used in certain circumstances and/or with certain settings. It is a well-known fact that the presence of dust particles cannot be completely avoided when using a D-SLR camera even after normal sensor cleaning procedures, because of a number of factors including components moving at high speeds when images are taken, the use of interchangeable lenses, and the different environments in which a D-SLR camera may be used. As part of its customer-service commitment, Nikon is providing a customer-service measure to reduce the potential impact of dust particles on images taken by its D600 D-SLR cameras.
The customer-service measure mentioned in this Advisory has already been performed on your D600 camera, serial number 30xxxxx, which included the inspection, cleaning and replacement of the shutter assembly and related parts of your camera, during your camera’s recent service. In these circumstances, your D600 camera, serial number 30xxxxx, is not affected by this Advisory, and it is not necessary for you to send this D600 camera to Nikon for this service.
We sincerely apologize for any inconvenience this issue may have caused. Nikon remains committed to providing only the highest quality cameras and components, and we hope that you will continue to choose Nikon for your photography needs.