Thanks for the suggestion, Ilya. I looked in the service manual; the diagram doesn't show a metal flap. It's just odd that they would put it on a 06 Maxima, but not in an Infiniti of the same era. Anyways, thanks!
Thanks, Edwoy! I was almost sure there was one. Your videos have been such a huge help! Do you happen to have an upper oil pan, front/back seals for the Ms coming anytime soon?