Does Catalytic chamber need to be replaced?

What stove make/model are you talking about? On most the holder is good, only the cats and gaskets need to be changed.

The catalytic element is usually a honeycomb-like structure that will start to fall apart as it gets older. They can still malfunction even if structurally sound if "poisoned". Poisoning can occur if something is burned in the stove that contaminates the catalytic metals (usually platinum or palladium) in the element. In either case, if you get the stove up to temp, engage the catalyst, and don't see a dramatic decrease in the amount of dark smoke exiting your chimney, the catalytic element is bad. I said dark smoke specifically because white smoke (steam really) resulting from burning wet wood can still be produced in a stove with a working catalytic element.

Check Condar Combusters website for a replacement price, and info on the care and feeding. You will go nuts if you believe all the inuendo on the net about combustors. They are a consumable part of a stove, and not expensive for the payback recieved. A good combustor stove will easily outlast other stoves since they do not require a raging fire to function well.
If I were inspecting a used stove, and wanted to know the cat conditon, I would look at the face of the honeycomb (if you can get to it. Take a good flash light, maybe a mechanics mirror). If the face is level or flat without crumbling or missing chunks and the surrounding gasket (if it has one) is solid, that is good. Color is hard to tell, but it should not be or clogged. A good fire is the acid test, and would reveal the true conditon. More important would be the condition of the firebrick and firebox. It is normal to have creosote in the interior of a cat stove as they do not need a raging fire to function, but a corroded interior is not a good sign. If I found a used stove in excellent condition, I would buy it without concern for the cat conditon. I certainly would not pass up a good buy on a car because the spark plugs needed replacing. My blaze king is 19 years old, I bought it used at a good price without worrying about the cat, knowing it was something that needed replacement, just like the door gaskets. I figure 50.00 bucks a year for cat cost, and that is repaid before I finish the first cord of wood I burn.
Let us know what you decided.

Sounds like you got an excellent deal. That 91 is a big heater... enjoy it.