Hi David,
Two points: for full disclosure, Rhino identifies a degree 3 arc as a “Nurbs Arc” as distinct from an Arc
And in Rhino 7 the SelArc scripts referred to, using the facilities provided by RhinoCommon, do now identify the degree 3 Nurbs arcs as arcs, without distinction from degree 2 arcs, whereas in R6 they didn’t. That was the gist of the original post. So, for the moment at least, I’m sorry, but your statement is incorrect.