Since 6.2 is substantially different from 7.2, I'd say the new packages are very unlikely to work for you. Red Hat 6.2 was a great release. But this might give you the motivation to upgrade to 7.3 once it's out, assuming your system is up to the increased hardware requirements (offhand, I'd say 400 MHz CPU, 128 MB RAM would do). Some software has gotten bigger.
One thing to note about the Red Hat packages is they replace KDE2 on a running system. From what I've seen of the Mandrake and SuSE packages, they preserve KDE2. However, my experience w/ Mandrake 8.2 is that the only way to choose KDE2 or KDE3 is from the console. From kdm, choosing KDE as the WM means KDE3; there are no separate options for the two major versions (which would have been nice for testing).
Also, the parent post that recommends installing the packages w/o dependency checking is not good advice. That defeats one of the major reasons for using RPM in the first place.
Instead, if you're installing what are essentially "foreign" packages, you need to determine what they require. RPM will somewhat tell you what shared libraries are prerequisite, but unfortunately, unlike
Mandrake's Software Manager (and SuSE's Yast2) will conveniently resolve necessary packages automatically for software that comes with the distro. Unfortunately, because of RPM's inherent weaknesses, they don't do so for "foreign" packages.
In general, I wouldn't recommend compiling unless you're a seasoned hacker. For one, your configuration will be quite different from the typical host used to build the other binaries. For two, KDE is a large suite of applications, and takes some times to build. Do you really want to build, integrate and test all of that yourself?