There was an edit history.

If you look at an archive.org of the old site - http://web.archive.org/web/20160709091504/http://c2.com/cgi/... for example, at the bottom the edit date is a link. That took one to the edit history showing the IP address that made the change and the diff. It was also something that was robots.txt'ed and so isn't in archive.org.