Replacing burnt up computer

I am going to the wreck yard tomorrow to pull a computer to replace mine in my car. I was told if I can find a make and model that match mine and take the computer along with the ignition switch and key and fuse box that I won't have to re program it or anything that the key will already be programmed to that ECU and I can just put the parts on my car and it will work. Is this all I need to pull tomorrow or is there any more parts I should grab and is this little secret true?