The trim rings are more cosmetic than for reinforcement as the hole saw left the edges rough and unfinished looking. They are actually cable grommets that you may see on a desk or table allowing wires to pass through. They extend into the airbox, and while I have no data to back it up, I would think they help keep the the cool air coming in through the clamshell from rushing out the holes.
looks OE :thumbsup i like it. that is some cool engineering right there :cheers