It's pretty clear that it's the same at the atomic level as well.
The spectra look exactly like they look here. They're red-shifted, but the gaps between the peaks are exactly the same. That comes from the atomic level, the way the electrons are arranged within the atom.
If something were different at the atomic level, it would surely change the characteristics of the light they give off. The only way to see what we see would be if there were two things different, that somehow counteracted each other in the things we can see but were nonetheless different in some other factor we can't observe.
That's not impossible, but it would be a bizarre coincidence.
