I never heard of an aluminum body model in the regular cars. A few had magnesium transmission cases to save a few pounds. Some of the slightly earlier Giulia spider models has slipper skirt pistons, to reduce rotating weight. I owned:Was that the aluminum body model?
67 GTV
66 Giulia Spider with 1600 cc engine and disc brakes. Great year for that model.
69 GTV
71 Berlina