Nice set! The 1934 in the lower row looks to have been cleaned, but the rest look like environmental toning.
No date discernible on top right one, and I was WONDERING whether the 1934 had been cleaned, or polished even? It's quite scratched, in a normal way, but has that light gold color.... really pretty but ...
Here's the bunch in reverse, in place. The "grain" of the 26 follows the same lines on the reverse, hard to see in my pic.
That's one of the appealing qualities of small copper cents - the wide variety of color shades from orange/red/golden to bown/dark chocolate