If there had been two handed swords in the EB period, wielded by Celts then possible names for such weapons might be;
*dualâmâtas (two-hander)
*marocledon (great-sword)
*cledon maron (large sword - Gaelic clamh mór)
So you could have Dualâmâtas Lugion, Marocledon Lugion or Cledon Maron Lugion. However, I think it's a futile exercise trying to reconstruct proper Gaulish names for units which obviously never existed.