Retrieve config files from phone

Is there a way to retrieve the config files FROM a properly working phone? I’ve got a couple of dead phones that I want to try and flash back to life. I have pieces of config files from around the web but I’d really like to get the ones used previously at our office. The previous ‘phone guy’ left on not-so-good terms and didn’t leave behind any instructions. I’m trying to pick up the pieces and I can’t find any config files anywhere.