@Bahrian best of luck for the sale. If it is bumper to bumper genuine with no spot no repaint it could have fetched close to 670-80.
But looking at rear bumper in 2nd pic - anyone would definitely want to look closely. I know it could just be the bumper and nothing else.
If it does have 2-3 pieces repaint like hood, trunk etc but no main accident - then it should value 6-630