A dual-purpose mounting structure and enclosure for a surface mounted surveillance camera system used alternatively to mount a camera system including back box directly onto a surface, or to mount the camera system such that the back box is recessed behind the surface. The enclosure and mount includes a back box having a flush flange assembly and a detachable surface mountable adaptor. For a surface mount, the adaptor is attached directly to the flush flange for mounting the enclosure onto a planar surface such as below a ceiling line. For a recessed mount, an opening is provided in the planar surface, the adaptor is inverted and placed around this opening on the opposite side of the planar surface, the back box is inserted through the opening and into the adaptor, and the adaptor is attached to the back box assembly.