When you install a source rpm, there will be a <package>.spec in the SPECS directory, and a tarball and patches in the SOURCES directory.
There are different phases that you can perform with a source RPM file, from %prep to %install. For example, if you run the command 'rpmbuild -bp <package>.spec', this will apply the patches. Then there is a directory in the BUILD directory that is the same as you would have if you had downloaded the same version tarball.
You can use another 'rpmbuild' command to perform the install. Actually, if you wanted to install it you would use this instead of 'rpmbuild -bp' at the start.
Here is a tip that might interest you. Suppose that you want to learn programming in the bash shell, and you want to print out the bashref manual. Install the bash-<version>.src.rpm package. Then apply the patches (sometimes the documents will change also) with 'rpmbuild -bp bash.spec' while in the SPECS directory. ( /usr/src/redhat/SPECS or sometimes /usr/src/packages/SPECS)
Then cd to the BUILD directory: cd ../BUILD
cd to the bash-<version>/ directory
Now run ./configure to produce a Makefile
Since bash is already installed, we don't need to make it. There are targets for the documentation.
Now the documentation you generated is in the doc/ subdirectory.
Because the documentation is being built from the sgml or tex source, the document produced is much better than what 'info bash' produces on the screen.
FYI, it's 154 pages long.
There are similar manuals you can generate from the coreutils package, the find package, the tar package and others. For very common programs, having a 3 ring binder for reference is a great aid.