The last time I played a modpack with GregTech, there was a difference between Aluminum (TiCo) and Aluminium (GregTech) and the two were not interchangeable. I think some of the newer mods like Galacticraft, Magneticraft and Immersive Engineering made a mistake and use them interchangeably, but originally Aluminum was a fairly easy to acquire item and Aluminium required special GregTech machines.
I think the wiki pages for Aluminum and Aluminium along with the disambiguous page should either reflect that they are different or note that they can be different depending on the modpack. or at least specify that only with certain mods are the 2 interchangeable.