You could always add the wiring for the temp idiot light if you wanted to. It is the dark green wire that runs from the gauge cluster to the ignition switch and then out to the engine. It is well-documented in the schematics, although you would need to connect it to pin 5 of the gauge cluster connector instead of how it's shown here:
http://67-72chevytrucks.com/vboard/s...d.php?t=185856