Issue the commands:
$ man gnome-sound-recorder
$ man 7 gtk-options
$ man 7 gnome-options
$ gnome-sound-recorder --help
$ gnome-sound-recorder --help-all
$ gnome-sound-recorder --help-gtk
$ gnome-sound-recorder --help-gst

Not much, but that is all there is. Looks like the options are more for
debugging than operational control of sound recording.