Well to be fair, the server installation and configuration is the responsibility of the end user, so the documentation will cover installation and upgrading on a pre-existing server.
However it will not (and in my opinion it should not) go in to any details regarding how to upgrade the OS from one version to another
in terms of support or Professional services, they would class this as a DR excersise, normally you would push across to a different server that has the correct OS requirements, or if you can spare the down time, just do it all in place on that machine.
Whether you can do a straight upgrade from Windows 2003 x86 to x64 is another story, i don't believe Microsoft officially support upgrading to x64 from x86 and you will have to do a full rebuild
https://www.linkedin.com/in/alex-allen-turl-07370146