How do you come to the conclusion that the temp gauge is reading too hot? How can you determine the actual coolant temperature with your IR thermometer? The IR device determines temperature from the energy radiated by the exterior of whatever it's pointed at. You can't read the actual water temperature inside the water jacket of a closed cooling system.
The sending unit is located in the head for a good reason: If it were located lower on the engine, when the cooling system loses pressure the temperature will never get over 212F until all the coolant has boiled out. Since 212 is within the normal range for a pressurized cooling system, you wouldn't notice the overheating before there is damage to the engine. By placing the sender in the head, once enough water is lost that the sender is "dry", it will indicate cylinder head temperature rather than water temperature, making the overheating obvious.
You might want to pressure test your cooling system.