1989 D... Could This Be A Class 6 Double?

That is Die Deterioration. The die wear is always on the side facing the rim. The LIBERTY will show this on the left side of the devices and the Motto on the tops of the devices.

The 1989 cents are a bit tricky. The design that year when towards wider devices. When you look at this years coins they are so different they make you think you have something that might be a doubled die. But the tops of the devices on the 89 might just be from circulation/counting/rolling the coins. There was an one from coppercoins that looked like the location of the mint mark. So I created a side by side of it and you coin:

Note that even this example shows the same contact mark on the 89. But not the width of the outside edges of the "9s'"? They are wider in this area. So while you eye caught the extra width of the bottom loop of the 8, I'm not sure that it is a class 6 doubled die. If it were, the outside edges of the 9's should be wider. But I would still keep it for now. You might want to submit it too coppercoins or at least an image? To see what they think before discarding it. They are not taking submissions for now, so it you will have to keep it safe for now.