I have an '06 and have watched my gauge with renewed interest in response to this thread
It's been ridiculously cold for the last two weeks, only rising above -20 today*. On start up my oil gauge goes right up to the max mark. Likely because of the thick(er) oil. (I use a block heater.) In a few seconds it drops to slightly above the middle of the gauge. Revving the engine will increase oil pressure for the first few minutes. Once the vehicle is up to operating temperature (slightly less than half way on temperature gauge) the oil gauge reads dead in the middle of the scale and never wavers.
The upside of this cold snap? I'm pretty sure I have a "real" gauge
H.
*PS - I know I'm a wuss compared to a Winterpegger