I feel like I remember that LM 105 had beryllium as a component, which is highly toxic. Apple would hate that. In fact they go to great extents to specify that their components are beryllium free in keynotes. So that would point strongly toward 106c imho.
106c: Composition: Alloy of Zr•Cu•Ni•Nb•Al 105: Zr-Cu-Ni-Al-Ti