System.map file does not have execute permission, so these tests will always evaluate false, and initrd will not be rebuilt.

...
    def copyExtraModules(self, anaconda, modulesList):
        kernelVersions = self.kernelVersionList()
        foundModule = 0
...
        if foundModule == 1:
            for (n, arch, tag) in kernelVersions:
                if os.access("/boot/System.map-%s" %(n,), os.X_OK):
                    recreateInitrd(n, anaconda.rootPath)

...
    def doPostInstall(self, anaconda):
        if flags.test:
            return
...
        if len(self._installedDriverModules) > 0 and len(self._installedDriverModules) == len(anaconda.id.extraModules):
            for (n, arch, tag) in self.kernelVersionList():
                if os.access("/boot/System.map-%s" %(n,), os.X_OK):
                    recreateInitrd(n, anaconda.rootPath)
...

I think you should have os.R_OK in these two places.