I apologize ahead of time, I'm gonna sound like a dick for a second. Since I can't remember everything in this thread, which I've read now a couple times, I use the search function like a normal person. I searched for "bearing" and "gasket', before adding this question, and couldn't find anyone talking about this plate.Again, read the thread. The metal plate you are showing is mentioned several times. Good luck on your new drive but I think your old one would have been fine after you got it cleaned up.
Edit: After searching some more, I did find a couple references to it being called a "stopper" plate. Sounds like some liquid gasket is in order.