If you have been playing with the Server 2008 Beta 3 and the Beta 3 DDK (also build 6001), you have probably heard from Microsoft that Server 2008 RC0 and WDK was released on September 24th. If you have MSDN subscription or access to Microsoft Connect, you can download the ISOs for the operating system as well as the WDK. Once I heard about that, it was time to upgrade to the latest and greatest 🙂
RC0 WDK installer by default wants to install in c:\winddk\6001. This would not be a problem normally unless you have the Beta 3 DDK installed which also defaults to the same directory. If you do choose to install in the same directory as Beta 3 WDK then there will be 2 identical looking entries for 6001 DDK in Add/Remove Programs.
The RC0 WDK Documentation installer on the other hand chooses to install itself at C:\Program Files\WDK Documentation\6001.070817 [in my case anyway] which differs from the Beta3 WDK Documentation directory [C:\Program Files\WDK Documentation\6001.070629]. Additionally the entry for 2008 RC0 WDK Documentation in Add/Remove Programs also had the build number appended at the end so it will look different from the entry for 2008 Beta 3 WDK Documentation. Note that RC0 WDK version is 6001.070916 [connect says it is 6001.16659.070916-1443] whereas the RC0 WDK Documentation version is 6001.070817.
I recommend you uninstall Beta 3 WDK before installing the RC0 WDK to avoid too much clutter and confusion around numbers after 6001 [although they look like dates].