How Dirty Could It Be?

Hi Folks,
Wow. This site rocks. So much info here. But I digress. I was vacuuming out our car this sunny afternoon, and I thought about the little grill by the passenger back seat. I got out my small but bright flashlight and got down to where I could look upward into the grill to see the filter mesh behind. It looked clogged and fuzzy and about 1/3 to half dirty (like an a/c paper filter in the house does). I pushed down on the seat corner (thanks for the tip on that here), and carefully removed the 12mm bolt using a 6 inch extension on the ratchet handle. I pulled up gently on the plastic that holds the grill and when I could get to the filter mesh behind it, I used the little brush attachment on my vac to suck up all the crud. I eased the plastic back down, then made sure the hole in the tab was lined up, then carefully inserted the bolt and snugged it back up. It made me feel better that I had helped the air flow over the battery. The car now has 32K and runs great, so I would like to keep it that way. My question is: Without taking the back half of the car apart to check the little fan that blows the air over the HV battery, can I just "assume" that with no pets and the little grill mesh no worse than it was, that it most likely is OK? Or am I just being overly optimistic? Thanks for reading this. And once again, for all the excellent, informative posts that you all take the time to publish. Hats off to the lot of you!