Nothing should be in contact with the metal face of these units, per manufacturers installation requirements. Also Fake Z-Brick uses a combustable adhesive. Suggest removing all that is in contact with the face of your unit before further use. Also do not use any accessory that is not tested and approved to be used with your unit. All will be listing in the installation instuctions that came with your unit. Although 16 year have past, the unit will have a I.D. plate attached to the inside panel of your unit. Request a new installation manual from the manufacturer. Do not use a Pennsylvania fireback, they are only made more masonry fireplaces.