If that were the actual temp, then you would likely throw a code. How hot is the upper radiator hose, can you even touch it?
What position is the temp gauge at when the key is off?
I agree it could be a stepper motor, the only PITA part of changing one is removing all the dials and getting them back in the correct spot. Also, a small roll of solder wick is your friend when removing them.
I use this:
MG Chemicals #3 No Clean Super Wick Desoldering Braid, 0.075" Width x 5' Length, Green: Solder: Amazon.com: Industrial & Scientific
www.amazon.com
Tip: When removing the dials, use a credit card under a dinner fork at the leverage point. Before you remove them, rotate the dials gently counterclockwise until they stop, then using some blue painters tape, put a piece under the dial on the cluster itself and take a sharpie and mark where the tip of the dial is.
When reinstalling the dials, only press them on halfway and confirm idle speed and MPH from a short drive with an OBD adapter and an app like Torque.