Here's a photo of the inside of the air filter assembly lid.
There's a compressed fibre seal around the outer circumference of the lid to seal between the lid and the can/housing and a rubber seal in the center that presses down on the filter element. There's the same type of rubber seal on...
All the OEM filters for the 1FZFE I've seen had a hard black plastic top and bottom. An aftermarket filter I bought once had metal ends The rubber seals on the filter assembly (can and lid) should provide a good enough seal IMO.