I looked at my original package tray, and I too don’t see any signs of staples in tray or the trim/gasket looking piece. Staples might not be a bad idea though, or some other method to hold the tray and trim/seal in place, to aid in getting the two into position without the trim falling off. Gets tight reaching back into the crevice where the trim sits at the bottom of glass line and back of the tray, if that makes sense. I didn’t mess with it too long, as it’s pretty hot here, and didn’t want to sweat all over the new package tray. Anyone else who wants to share their experience would be welcomed. Perhaps there’s more than one method the factory used in installing these? Attaching a couple more photos of the piece I am referring to.