Temp Gauge Offset?
 

I just had the oil changed in my car and they also changed the Crankshaft Position Sensor because it was acting up.
Got my car back and noticed while I was driving that the Temp gauge was in the red. Turned the car off to check things out under the hood and noticed that with my car turned off the gauge didn't return to zero (or cold). Lots of coolant, oil level was fine and when I poked my head under the hood nothing seemed to be overly warm.
The shop I took it can find nothing that they would have done that could have caused it, dealer is claiming without even seeing the car that I'll need to have my instrument cluster replaced. I don't want to take it into the dealership if I don't need to and I plan on reading the codes off it tonight.
Has anyone else had this problem? I don't believe it's the ECT Sensor because in this case I don't think it would return any value or have some intermittent problems. The gauge although reading incorrectly seems to be very stable. Even when sitting for a long period of time the gauge holds at about midrange (proper operating temp) and the gauge seems to react normally just shifted to the hot side.
Anyone else ever run into this? Have any ideas on what it could be?
I don't want to go in and just let the dealer hose me.

Cheers, any help would be appreciated.

I'd change the coolant temp sensor before the cluster - they're common and can fail in several different ways.

theres a stick on the forums that gives common problems and solutions try the coolant sensor its worth the fix only 25 then theres another one where it sais your gauge is actually stuck and if yours does not go down when you turn it off then i think it is