Reconfigurable intelligent surfaces (RISs) have been considered recently for target localization. While existing literature typically uses fixed RISs in the environment, mounting RISs on targets is a novel approach that can improve target visibility and positioning. This study derives the Cramér-Rao bound (CRB) for pose estimation (i.e., RIS position and orientation) under a generic wideband and near-field model. The theoretical findings show that a pose-dependent filtering phenomenon occurs, impacting the CRB, which is neglected under narrowband approximation. The extent of this effect varies based on factors such as RIS dimensions and signal bandwidth.