Hi,
I checked this in different manuals (F-4C/F-4E/RF-4E/RF-4C/FGR-2/
FGR-1) from my collection (don´t have a G-model manual,though...)
There are more switches on the left and right throttle: side,back and
front.
But you ask about this switch on the left throttle.
On the left Throttle you find the strike camera control switch. Camera
on/off....but this is a flip-switch.
A push button, the engine relight button(the right throttle has the
same one, naturally), and a push-button, the towed target drop-switch.
In two of the manuals (F-4E and FGR-2) I found this "Towed target drop
switch" on the left throttle handle-front-side (heading nose of the
aircraft). The other named switches are on the handle-back-side
(heading tail of the aircraft).
....and now I hope I am right here.....I never worked with the
Phantom, I am just a PHANTOM-PHREAK :-))
Spooky