That depends on what type of "lift rings" you are referring to. Most of the models have jack lugs located about the middle of each truck on both sides. These are welded to or are an intergal part of the frame and are designed for either jacking underneath or lifting. Some were designed to take cable slings to pick the whole body/frame up together. I know the S series have them, the RS's and the Centuries. Actually, since I am thinking about it, I can't remember seeing any that didn't have them.
Is there a specific type lift ring you were asking about? There are also other mechanisims for lifting whole engine blocks, main generators or hood sections off.
Buffalo Southern Railroad