Same tow bar and fittings. There's actually no difference between the 3 and 5 door, below floor level. Same chassis rails and drive train are used on both. Even the wheel base is the same. It's only the body panels on the top of the chassis rails that differ.
The inner sill member is a different shape, as is the outer sill. So I wouldn't think that steps for the 5 door would fit on the 3 door. You would find that the mounts and holes will be incorrect.
