i wanted to ask something regarding our Front Disc Brake(the rotor),is it normal for them to be very rusty on the part where the brake pad dont touch?

my set of disc brake have been claim last month and i notice it will rust very quickly compare to what i used to have that is the old batch disc brake where it will vibrate when we step on it.

i also notice that newer myvi 2007 batch or myvi SE has a disc brake that will not rust,the part that is not touch by the brake pad seems to be like coated or paint with something that the colour look like primer and its anti rust i guess.