68 A-body ash tray is one year only because of the lower dash pad on all 68 A-bodies cars. The ashtray slides out like you said. The face of it is fairly flat with a ridge to grab it from. All 68 A-bodies have the same ash tray.

They can get a little messed up with the ball bearing in the sliders and all.

Here's the best picture I have at this computer right now. It's a picture of Troy's Hemi 68 Dart. Maybe someone can post a better picture.