not really. Logitech shape the mouse so that your thumb and pinky fit nicely around the sides.
the downside is that it's only works well for right-handers (though I don't know anybody who uses a mouse in their left hand)
this is the G5 (I have one)
this is the MX-510 (I have one of these also, but it is red)
the Logitech shape is about the same for the MX500, MX510, MX518, MX1000, G5 and G7