Downloaded the IGES Parts Library v1.5. Have only looked at the Linear Rail profiles so far, and noticed small differences between the C-Beam and V-Slot extrusions. I just assumed they would be the same but they're not; and I don't have physical samples yet to compare. Just thought it might help someone else while designing.
Some of the CAD models are a little out of date, and V-Slot and C-Beam are 100% compatible and the same radii and distances in real life.