My father has had this Auto rallye for years. He used to work for a industrial plant that used it as a calibration device. It works perfectly and looks to be in great shape. I couldn't find any other example on the internet where the dial was inverted like this one. He's has an interested buyer but has no idea how much it is worth. Any help with the value would be greatly appreciated. The pictures aren't great because he isn't real proficient with sending me stuff over the internet. But the back reads... HEUER LEONIDAS SA SWISS 18.8433