Finding original files in the Mac OS X installer
When I first commented on your question, I was hindered by not having discovered httpd.conf on my own system. Now I have found it, however, and I can find out what packages owns it as follows:

; pkgutil --file-info /private/etc/apache2/httpd.conf
volume: /
path: /private/etc/apache2/httpd.conf

pkgid: com.apple.pkg.BSD
pkg-version: 10.8.0.1.1.1306847324
install-time: 1352382423
uid: 0
gid: 0
mode: 644


Note: com.apple.pkg.BSD is a package name, not a filename. You can find a list of all packages that pkgutil knows about by running

pkgutil --packages


Also note that running the above command on /etc/apache2/httpd.conf does not yield a useful result, because /etc is a symbolic link to /private/etc.