Hi Jay,
I too have a brain that shows the same symptoms at times :-)
I reported the missing icons from the Ribbon sample in 6.3, which I also could reproduce in 6.3.1, in an issue you can track here.
Regarding the Catalog versus SDK version, then if you look at how the SVN source code is organized, you see that the SDK and Catalog are maintained within the same repository, so they "stay together". Don't know exactly when the Catalog sample is updated, but if it is showing 6.2.3, then it's from within 6.2.3 SDK running the 6.2.3 Catalog app.
Palli