I have been trying a lot of different things out on my Pi. Some of the Expansion cards asked me to put
# in front of certain lines.
As the sole user of your Pi and thus as acting system administrator the task of backing up config files before editing them is your responsibility. They're usually not automatically saved to another location. If you edit them you better make sure you have a working backup beforehand. That being said it is of course possible to obtain the files you're looking for:
If you have installed your Raspbian from a downloaded image (e.g. as described here) and have that image still available you can mount the image and search the files you're interested in. This question: How can I mount a Raspberry Pi Linux distro image? outlines what needs to be done to mount the image. Note that config files may be updated by the package manager. So if you have an old image and an updated system there is the remote but existant chance that the config files are different.
It should also be possible to retrieve any files from Raspbian's online repository.