These don't indicate overbuilding. It just means you are off the cliff as soon as your cash flow turns negative.
Buying a house in this area is like condemning yourself to walk around with a huge sword hanging above your head.
If you were looking for something that indicated overbuilding, I would look for declines in the ratio of rents/sale prices to median metro income. If housing is getting cheaper compared to incomes, that means supply is catching up to or outstripping demand. This could happen regardless of boom, bust, or stagnation.
See http://www.usnews.com/news/best-cities/slideshows/the-10-mos... and http://money.cnn.com/gallery/real_estate/2012/11/29/least-af... for examples.