I think they're chrome plated copper
I too have a Coffee Master vacuum pot. Picked it up at an antique fair here in Sacramento, there were two available. One had a cracked rubber gasket, the other was unknown as it was stuck together, but appeared to be in better condition. I pulled it apart, with help. The gasket is perfect in appearance, and pliable when heated.
Mixfinder: thanks for the glycerine hint, I knew that something would work to help the pliability.
So here's what I do. I place a large plastic glass of water in my 700r Radarange for two minutes (I start with hot tap water). Then I place the upper pot in the hot water for a few minutes, the gasket gets nice and pliable. Then I insert it in the lower pot, full of cold water, place the washable filter and coffee. After the coffee is brewed, I disassemble and clean the top pot. They really make nice smooth coffee, supposedly the temperature is not too hot to make it bitter. And as mentioned the drama is fun, mine is placed on a formica counter, which sets up a vibration similar to a volcano going off.
Martin