Usually, big products have their own codename. Every Linux kernel release has their own names, even though it's never being published sometimes. Mozilla, Windows, KDE, and Ubuntu are examples of products which have a unique names for every release.
This is not what happened on OpenOffice.org. In the past (OpenOffice.org 2.x), they used a specific notation on the about dialog about product versions to distinguish between Beta, RC, and Final release. Currently (OpenOffice.org 3.x), they do not use those kind of naming again, mostly for Final release. What they use is just a build number and milestone (CMIIW). For example, OOo 3.1.0 has a release information: m11, Build 9399.
I think this information might be confusing for some people, because they *may* not know which one is the final release and which one is the RCs. Just a small hint, on OOo 3.x development, the last RC will usually be the final version, so those packages will go into stable directory on every OOo mirror site. Every time a new version comes into stable version, you can say that that's the final release. To be sure, you can wait for few days and make sure that you got the correct build.