Hi there,
You are better off just getting a digital thermometer with probe end. They are easier to use and you don't need to worry about their accuracy based off the material you are measuring.
To not get too technical, temp guns rely on a specific calibration and a specific group of materials that fall in that calibration. If the material you are measuring isn't the type of material that your temp gun is calibrated for, you won't get accurate readings at all.
This can be compensated for by getting a temperature gun with an adjustable emissivity setting but even then, you'll have to know the emissivity of the item you are measuring.
Digital with probe end thermometers don't have this issue, and will work on basically any surface, including the air.
-Brandon