I finally got my camera back today from Nikon service. It was on "parts hold" forever. In all my camera was out of my hands for 41 days which I think is unacceptable. Even if it took 6 days in transit (it only took 5) that still means they had my D600 for over a month. It was listed as parts hold for almost a month! I will see how it performs tomorrow and over the weekend.
The repairs were listed on my receipt as follows;
RPL shutter mechanism RPR pop-up flash CKD communication CKD shutter release CLN low pass filter Firmware upgrade General clean and check General clean and check General clean and check
I assume the last 3 items were dust removal?
So there you have it. Hope to have as many years of use out of this now as I have had and continue to have out of my D80.