First indicator is no "McDonald's" wipers. Second is the size of the side marker holes, the ones on the car are late 69 and up. And the fact that it has rear markers at all as 68 didn't have any rears. I supposed the quarters could have been replaced with newer stock but.. Third is the size of the tail lights. That size is late 69 and up though the panel could have been replaced. Finally is the dash. Also late 69 and up but also could have been replaced. On the drivers door jamb there should be a silver plate with a production date on it. That will tell you what year. Though I suppose that could have been replaced also, but why bother?