Coinbuf

I would avoid Littleton and Ampex, imo their prices are retail+ or higher.   For slabbed/certified copper cents, two cent pieces, and buffalo nickels I highly recommend AngelDees.  Link   Andy does tend to focus on the high grade coins (as most dealers seem to) but he does have some select lower circulated graded coins too.   He is one of the top Lincoln specialist dealers that I know.   For raw coins if you can find a local dealer that you like and trust I have found that to be good source in the past.

An abused entry in my 7070 set.

Plated, mercury plating was done often in schools for chemistry class.   Nickel plating is another possibility as the guys that work in chrome plating shops love to have some fun and nickel has a weak attraction for a magnet.   As Neo suggested whatever was used to plate the coin has begun to wear off over time.

Looks plated to me.  The toning could be copper peeking through under the plating.

Does not look like a DDO to me, plating blister or die damage is more likely.   Bob's advice to post on the CONECA forum is good advice, if they think you have something they may request you send in for an in hand review.

An abused entry in my 7070 set.

Your coin is not one of the so called SMS coins, just a normal brilliant proof.

An abused entry in my 7070 set.

Hello and welcome to the forum.  

An abused entry in my 7070 set.

An abused entry in my 7070 set.

Your coin is not one of the so called SMS coins, just a normal brilliant proof.

1885 Liberty nickel, now NGC graded XF 45:

1893-CC Morgan dollar, now NGC graded VF 30: