No, “solid modeling” is only a theme for orienting the user interface and feature set. All CAD systems today use NURBS to build geometry, but a “solid modeler” never lets you do anything that leaves the model in a non-closed state. So the model is always at least theoretically manufacturable, but the workflow for making curvy shapes is unnecessarily convoluted.
Of course that definition is decades old and increasingly not entirely true, today “solid modeling” means history-based everything-plus-the-kitchen-sink mechanical engineering, and “surface modeling” means Rhino.