corrected it for you.
Now let me correct it for you:
"Spangenhelms were ALL over europe because the Romans and eastern tribes used them en mass. They were the basis and mainstay of most nations helmets through the EARLY / MIDDLE middle ages."
If we add that, we can add roman legionaire armors too 
No, you would not need to add "roman legionaire armours". Could you also define exactly what you mean by that anyway? The cliche Lorica segmentata? Because that wasn't even used widespread during its peek, and was only partially around up to about the late 3rd / early 4th century.
You have to remember that Rome generally didn't invent their weapons, they stole the ideas off of other countries around the world when they saw they were effective. Rome spread far and wide and had a great influence on many countries and cultures long after it collapsed. Roman armours and weapons / derivatives were widely used all over Europe and the Middle east throughout the entire Medieval period actually. Although more commonly the early / middle period.
You'll actually find that "Roman" derivative armour is actually already in the game...
The Lorica squamata / Lorica hamata (scale / chain armour), which were far more prominent in the Roman army throughout. It was also the standard issue for late period Rome. Indeed, even the Viking swords are derived from a Roman sword, the Spatha.
Spangenhelms were adopted and used by many countries for a long time, a big reason for this was that it was relatively easy to make via riveting pieces of metal together. Kettle helmets and bascinet became very popular too for the same reasons. Poorer armies / units continued to use whatever they could get their hands on for a long time. Especially Gaelic / Eastern countries which used the helmets quite late.
Not everyone ran around in plate armour, you know? It was very expensive. The mod includes early and middle period armors, shields and weaponry such as Viking, Kevien Rus, Saxon and Norman kit to name but a few... (We should probably remove cataphracts too?) There is literally no reason to not include some Spangenhelms. Especially not "LOL ROME HEHEHEHE".
