My original 78 came Radio Delete, so I had a blank canvas if you will. The Package Tray was solid no holes, and a combination of some kind of paper/thick tar/cardboard....What I did was use the holes in the metal part as a template, and sawed the openings out through the previous described cover, drilled holes using the metal part for the screws. The speaker grills had studs so all I had to do was drop them in place and then from inside the trunk I held the speakers up to the bottom of the tray, started the nuts and washers, tightened everything up and called it good. The TA I have now had a factory radio, and the guy I bought it from pulled it and the speakers, so again its kind of a blank canvas....just 6X9 holes only I don't have to cut through that tar stuff, just put speakers in.