Probably no effort being put into this as it has been the default for several releases now.
The advice I found was derived from changing buttons from left to right as:
gconftool-2 --set /apps/metacity/general/button_layout --type string menu:minimize,maximize,close
but it can be made to work the other way as well.
I'm sure I had a way to do it by directly editing a text file, but can't lay my hands on it