There aren't two sizes of Schwinn Rams Horn bars, just one size. You can tell if they are the Schwinn bars if they are marked Schwinn Rams Horn in the knurling on the bars where the stem mounts.
Wald made the bars for Schwinn, so you will see variations of the same style bars, but stamped Wadl in the middle and shaped a little differently than the Schwinn version of the bars. You can usually tell them apart by the angle of the bars, the Schwinn bars come more straight up from the bottom bends, where the Wald versions are angled out a little more.