If a 1999 Chrysler Sebring ignition switch cylinder is installed by other than a Chrysler dealership does it have to be programmed?

Yes. If you have a grey key, it has a transponder that electrically reads a chip in the key. You essentially have two locks -- one mechanical and one electrical. They both have to work to start the car. Should you go and have a generic key cut that fits the ignition, even thought the mechanical lock cylinder will turn -- the transponder won't allow the engine to fire.

Any quality locksmith can program the car's transponder to match the electronic code of the key.