No but it is machine doubling the 1954 and 55 had a omm variety,but I'm not seeing the omm matching any listed from the image provided.
It very well could be. The top of and the left side of the D look correct. However the inside of the D is lacking detail. Better and clearer photos are needed or you can take to your LCS. Both the 1954 and the 1955 had overmintmarks. The 1955 was a D over an S. I didn't vote because I a maybe. Welcome to CT.
There are 12 known omm's for 55 none show the flat shelf like the op does, the nickel West side looks as if it slid Eastward from a bounce not a repunched die
Thank you for clearing up my confused state. It's as clear as a crystal ball with mud on it. However it makes sense and that almost scares me. I'm laughing at this.