It would be news to me. Perhaps you have mistyped a 4 and 3 being a key off for each digit instead of typing a 5 and 4 for 1954.
There is a 1954 S over D. There are numerous same repunched mint marks on
War Nickels but they are the same letters. P over P, D over D and S over S.
If there is a 1943 S over D nickel, especially if it is legit and dramatic, I think you will have something quite unique and valuable.