I believe this model was made by Paul Deyo; I grabbed the picture from this Fusion 360 hangout.
In the back is a mesh model, scanned from a physical part. The part was then brought into Mudbox and retopologized, then converted to a T-spline body before ending up as NURBS.
The cool thing about this is that you start with a piece of extant hardware and end up with a well defined, symmetrical, editable part. This is really, really powerful.