If it's original and came with the rear heated backlite. then it's permanently bonded on to the glass while going through the furnace and should have a black band around the outside to hide the wire soldering points and connectors. those were silk screened on using a ceramic paste made with somewhere between 97-5 to 99.2% pure ground up silver and glass paste so that they could melt into the surface of the glass and bond well. anything else is an add on.