They are by design fairly different exercises, with the form intersection vehicles just being an arrangement of primitive forms in the general likeness of a vehicle (but still just like doing the regular form intersections exercise), and the actual constructions involving starting with a bounding box, subdividing, etc. and then building up more specific forms within that structure with a focus on precision. So you really wouldn't be in a position to reuse them (although if you were, the only benefit there would be decreasing the workload, which also means getting less practice out of the lesson) - so no, you should not be doing that.