I can’t imagine how its possible; you have to drag it from one to the other in in the pref pane gui, and in ~/Library/Preferences/ByHost/ there is a com.apple.preference.displays.xxxxxxxxx.plist file that doesn’t have which screen the menu is in in clear text.
set thelist to (list folder ((path to home folder as string) & "Library:Preferences:ByHost:" as string))
repeat with i in thelist
if i starts with "com.apple.preference.displays." then return (i as string)