This looks like what we call album toning, but since there are so many, it's likely due to sitting in a roll. Very likely, these sat in a roll that caused them all to tone from outward in. I don't see them having any added value/premium, but keep any you like.
The one with complete toning was on the end of the roll. The rings were inside the roll. Depends on the condition where the roll was stored that affects the toning.
I have quite a few rolls of these 05' 06' that have toned the same way. Could be something in the paper they were rolled in. ? We're they in US mint rolls?
Just toning, also known as environmental damage. Some collectors love toned coins, other don't. Unless it is a rare coins with just the right toning, there is seldom added value.