Those are in these locations on Mavericks:
Note the capitalization - lowercase mail, capital Maps.
To read and set window frames:
defaults read com.apple.Maps "NSWindow Frame MapMainWindow"
defaults write com.apple.Maps "NSWindow Frame MapMainWindow" '2056 137 1000 712 1920 0 1440 878'
It seems though that some apps (maybe those with AppNap) don't obey the new preferences immediately, so you may have to log out and back in. Maps in particular doesn't seem to work properly, and in Mail, the main window is in a sub key. You could, for example, do:
defaults write com.apple.mail "NSWindow Frame Compose Window" '175 36 718 779 0 0 1440 878'
to set the compose window frame. It all depends on the key you're trying to set.