Those are the plates that came in the 2", 4-plate reflux column I got from Oak Stills. The caskets came with it, I think they are silicon.
I do appreciate all the information I've received. Its been a huge help. Clearly this stuff is more durable and forgiving. My stomach just turned when I saw what happened from not rinsing the vinegar off.
Good to know it's easily corrected in several ways! (Not sure I'd have run a batch through without cleaning it again though..