The content is all from contributors. You can edit/contribute to it if you want. That's how wikis work. Chances are it's 100% unaffiliated with DC Comics.
You are correct. I just wonder who took the time to monitor/compile all the information originally, Speedy? The poster you quoted, DC Wikia, does he have no relationship with DC comics whatsoever? These are the questions Id love to get answers to.
When I look up an indivual on Wiki, I get the impression it is either that individual for a PR rep who compiles and monitors the information. I don't think it's a huge stretch to assume the same may be the case here. After all, if the data were left unmonitored, and if the public were allowed to edit the info unconditionally couldn't we assume that BB 54 would be listed as a first appearance as well. As you can see for yourself, that is not the case:
http://dc.wikia.com/wiki/Brave_and_the_Bold_Vol_1_54