The armor is supposed to be a gold-titanium alloy (which a fictional composite material) to make the Mark III which carries over to the Mark VI. Now, while gold is naturally gold it can be turned other colors by alloying gold with other materials. Therefore if its composed with titanium it would turn things more a silver color in theory. As far as if it would make for a good armor or not "according" comic world the Mark VI armor can take a beating and keep on ticking without taking much damage.
Now, as far as the scratches being silverish or gold. Lets assume by mixing the gold and titanium enough it makes it more silverish (white gold type color) that would make sense to me. Thats why I would think knowing how the two would mix not keeping it gold colored anyways. Its fun to talk about but its looking into things harder than I would normally care to. I mean in Invincible Iron Man the BE Armor comes out of the pores of his skin. So while the movie is bent to the real world it is still truly fiction.
Now, as far as the scratches being silverish or gold. Lets assume by mixing the gold and titanium enough it makes it more silverish (white gold type color) that would make sense to me. Thats why I would think knowing how the two would mix not keeping it gold colored anyways. Its fun to talk about but its looking into things harder than I would normally care to. I mean in Invincible Iron Man the BE Armor comes out of the pores of his skin. So while the movie is bent to the real world it is still truly fiction.