Nice gun! Those 4" barreled HD's look just right and so tough.
It's ashame someone harvested the HBH and the pre war magnas.
My first nickel Heavy Duty came to me the same way - wrong stocks and a regular pre war hammer. Fortunately it still had the original barrel. I had it lettered and it and it turned out that it was configured just like yours. After much searching, I was able to find a humpback hammer and a correct set of stocks.
Interestingly my gun shipped over a year later, but has a much lower serial number than yours. It looks like there was a 10% price increase as well.