It is possible with the G-Force to send out a Program Change when switching preset?
Yes, but the G-Force will normally only send program changes when you recall presets manually, meaning that it doesn't send any program changes to its MIDI output when you switch presets from e.g. a MIDI pedal.
However the G-Force's custom MIDI mapping, in conjunction with the function "Retransmit to MIDI out", allows the unit to switch to e.g. preset no. 6, when recieving program change no. 1, and at the same time transmit the original (recieved) MIDI program change (which in this case is no. 6) to its MIDI output.
So, if you set the G-Force to "Custom mapping", but without altering the destination preset (meaning that incoming no. 1 also "maps" to no. 1, and so on), and activate "Retransmit to MIDI out" for each preset, the machine will behave as normal, except that it will send out the corresponding program change every time you switch preset from your MIDI pedal.