Yeah very little saving but combining all the little savings makes a difference.
For example fenders are made up of fiber glass not metal
Unpainted Engine Bay only primer
No Spare Tire
Unpainted door handles on lower versions
Thin door panels plastic
Fixed grab handles not those which fold up
Etc etc ...
Adding all these up and more which i dont know would make somewhat savings.
You can clearly see 1 lac difference between alto and wagon r and the reason is these small things like tray under neath the seat, rear headrests, rear reclining seats, rear 50:50 split seats, rear adjustable seats, lights with sun visors, standard climate control, powered mirrors. These are small things which amount upto 1 lac easily i guess