The electrical contacts on the lens are spring loaded. If they all project out the same distance, it would not be the cause of your problem. Sometimes one of the electrical contacts will pop out though that is rare and very unlikely to happen to two lenses.
Neil Rothschild (nrothschild) had an electrical contact on his D300 camera body erode enough to prevent the camera from communicating with the lens. He included some images. If you search the D300 forum, you can compare it with your D300. (I would post a link but I am posting from my phone.)