PXE boot files question

I have a working PXE server running for many flavors of Linux and Windows. The question I have is, are the 'initrd.gz' and 'linux' files the same for all versions of Ubuntu other than the arch?

Meaning are the 'initrd.gz' and 'linux' files on the Ubuntu ISO's the same as the ones on the Kubuntu ISO's?

Yes linux (kernel) and initrd (Initial ram disk and kernel modules)
are exactly the same if the there the same release version and arch.