The models are totally different, if you can't see the difference, you aren't looking hard enough.
Look at the ridge that runs down the middle of the blade. On Skele's model, it connects directly to a vertex of the triangle at the top of the grip. On the Gmod model, the ridge completely misses the vertex of the triangle.
Also, the grips are shaped differently. The upper part of the grip flows directly and smoothly into the hook of the blade on Skele's model. On the Gmod model, the angle between the hook and the grip are different, which makes a small corner there.