I recently moved and had to replace the AAA batteries in my Honeywell RTH111B1024 thermostat. While looking, I noticed there's two options in the lower left corner for Gas/Oil or Electric/Heat Pump.

Originally, it was set to Gas/Oil. I left it as such, but according to the official manual, it states:

Electric or Heat Pump: Change the switch to this setting for heat pump or electric heat systems. (This setting is for systems that allow the thermostat to control the fan in a call for heat, if a fan wire is connected to the G terminal.)
There's a G (Green) wire connected to the terminal. Does this mean it should be switched?

The most I can provide (other than the pictures below) is that I have central air/heat and the handler is in the closet above the water tank. Unfortunately, I cannot tell you about the AC unit since it's located on the roof of the apartment complex. The access to the attic is caulked/sealed, so no entry.

Thank you!