What do these traffic signs indicate?

You answered correctly. This sign combination means stopping and parking are both prohibited on the entire roadway and the hard shoulder. The upper sign is the no stopping sign, and the lower addition indicates the restriction applies not just on the road itself but also on the hard shoulder. It is important to recognize that this rule does not only apply to trucks or just the hard shoulder—it applies to all vehicles on both areas. For questions like this, always pay attention to any additional signs below the main sign, as they often clarify or extend the restriction.