I noticed that one of the articles in an SE site's help center is "What does "beta" mean?" It gives a quick run-down of all the important information about beta sites. This is helpful for new users on beta sites.1
The article (which is similar, if not the same, in many non-trilogy sites) starts off with
This site was created through the open democratic process at Stack Exchange Area 51, and it is currently in beta.
On the other hand, sites that were not created via Area 51 do not have the message. Stack Overflow just begins with
We create beta sites through the open democratic process at Stack Exchange Area 51.
The same goes for Meta.
Moderators can edit some help center articles (such as the on-topic/off-topic pages), but I can't edit the page on HSM, even though I'm a mod (as per this post, I believe - only some sections are editable). So it's fixed.
I realize that it's something minor, and that not many users will ever reach the page, but can that be changed when a site graduates?
1For those that go through the help center, that is.