Yes, you could do that. But that still doesn't mean it's good, or accurate.
With a 5K-ohm variable resistor, (VR) you could probably test it properly. Most of the fuel gages in the military are about the same. The sending unit is a variable resistor. When a 5K VR is adjusted with a multimeter, 216-265 ohms, then hooked up to the meter, (pos side to S terminal on the meter, and neg to the G terminal) and then 24 volts applied, the meter should read about empty. When the VR is adjusted to 29.7 - 36.3, the meter should read full. The reading can be about 1/8 inch off, one way or another. I could post the whole procedure, its from a gen set, but most gages, like I say, are about the same.