Hey,

if you're uncomfortable with editing the config files, or you don't want to loose any panel under the standard 'shift+#' hotkey,
you can always go to the 'View' tab in the fsx toolbar, choose 'instrument panel' and click the one you want, for the spectre, the gun panel is listed...
I do it that way, since it's not much slower, and you can't do anything wrong :P :P

Tyrion