1994 Astro ECU

I have a 1994 Asrro van that I am replacing the ECU on. purchased the new ecu (remanufactured) from a national auto parts chain. I asked them if the ECU would have to be programmed. I was told that all I had to do was take a module from the old ecu and put it in the new ecu and I should be good to go. I confirmed my vin number and the part/model number off the old unit. When I put the the new ecu in the van it sputtered once and would not start. I put the old unit back in and it runs as it did before. The parts store will not take the ECU back they will only exchange it. Here are my questions

1. Does the ECU need to be programmed?
2. If it does, where do I get that done?
3. If I plug in the new exchanged ECU without programing it to see if it works, will it damage the unit?

Thank you for the help.