I am using Lightroom 5.7, and I import .nef files (Nikon D800).
I import the .nef files without any Quick Develop settings (set to 'None'). My default presets are not specific to the camera serial number, and also not specific to the camera iso setting.
However when I open the image in the 'Develop' module, some values are not set to zero: e.g. tint +25, sharpening +25.
My question is:
Has Lightroom already pre-modified the image, or is it just reading these values from the file itself?
Tint would have been calculated by your camera as part of the white balance calculation.
The +25 amount of sharpening is the default sharpening applied to all RAW files.