Was the radiator replaced because it was leaking or plugged up? The water pump is driven by the timing chain and takes about 4 hours to chance. I haven't seen failure and wouldn't be to rushed to change it. I am sure the radiator and cooling system hoses were inspected when the radiator was replaced but it might be worth asking the repair shop that replaced the radiator to closely inspect the hoses if the radiator was replaced due to restriction. If it is determined that coolant hoses need to be replaced it would probably be prudent to change the thermostat seeing as the cooling system would be drained any way.
Jon, based on what you have said the radiator had a leak, you replaced the radiator. It has fresh coolant and a new radiator. If the engine temperature gets up to operating temperature and your heater works well then the thermostat is operating correctly in the closed position. If the temprature reaches half way or a little over half way as you drive the car the thermostat is opening correctly. I would wait until the coolant needed to be drained or the cooling system was being worked on in the future to replace the thermostat.