The manipulation of virtual 3D objects is essential for a variety of handheld AR scenarios. However, the mapping of commonly supported 2D touch gestures to manipulations in 3D space is not trivial. As an alternative, our work explores the use of haptic props that facilitate direct manipulation of virtual 3D objects with 6 degrees of freedom. In an experiment, we instructed 20 participants to solve 2D and 3D docking tasks in AR, to compare traditional 2D touch gestures with prop-based interactions using three prop shapes (cube, rhombicuboctahedron, sphere). Our findings highlight benefits of haptic props for 3D manipulation tasks with respect to task performance, user experience, preference, and workload. For 2D tasks, the benefits of haptic props are less pronounced. Finally, while we found no significant impact of prop shape on task performance, this appears to be subject to personal preference.