Yes, at the dealer I work for we have a device that checks the guage using veriable resistence. You hook up the device to ground and to the wire at the sending unit and turn the knob. This causes a resistence that changes as you turn the knob.
When the knob is at its lowest setting the guage reads cold, middle setting reads normal, and highest setting reads hot.
So with that in mind ground the wire st the sending unit (with the key on) and see if the guage moves to hot.
Ya know I wrote all this and it occured to me that you may have a mechanical guage. If so, boil a cup of water in the microwave drop in a thermomature when the temp gets down to 190 drop the sending unit bulb into the water and watch the guage.

I didn't do it, no one saw me do it, you can't prove anything! "Bart Simpson"