A good way to see the difference between polished stainless steel and chrome plating is on your flag mirrors. The flag is polished stainless and the base is chrome-plated metal of some sort. The flag gets bugs and other debris that is cleaned and polished time after time. When they were brand new, the flag and base looked almost the same. Years later, the stainless has all of those micro scratches that can't be hand polished to look like the chrome base.
The stainless bumpers will look great for quite a long time,but constant cleaning will give them a patina.
That will still look better than the pitting and corrosion of the very old chromed steel bumpers and the USA diving board bumpers.