That's a great site -- they cover some obscure codes that saved me in the past.
I couldn't consciously run it with a bad cat or sensors, so I'd have to fix it should it become a continuous problem. The goal of retaining the car is a combination of environmental and economical reasons, so those two factors sometimes don't agree.
Nevertheless, it would be a great time to replace the whole rattling exhaust system.
We'll see if the code returns...
-Rick