The menu items looks exatly like the old quicktime 7! with no new items.
No new menu options are added by keying QT 7 for "Pro" use. However, some options that were previously unaccessible (grayed out) will now be accessible. For instance, can you now open the "Properties" window (under the "Windows" menu) when a file is loaded in the QT 7 player app? If so, then the app is correctly keyed for "Pro" use.
Did I miss something?
Hard to say without actually seeing your system. Did you follow the instructions listed under the "Additional Information" heading on this web page?
What is the difference between the Quicktime Player installed by default with OSX 10.8.2 and Quicktime 7?
QT X is Apple's attemt to modernize QT by completely rewriting it to make better use of newer and more efficient video tecnologies—unfortunately, at the cost of compatibility with "legacy" video technologies and editing features developed over a two decade period of QT evolution. As such, QT X is still in its infancy and, on the one hand, still lacks many of the features and capabilities now taken for granted in QT 7 Pro (like layer compositing of content at the track level), and, on the other, adding new features (like the playback of "transport stream" files or native support for MPEG-2 GOP and AC3 content) which are not possible in QT 7.