Yours looks to be original. The removable "for display" panel was a feature of many boxes beginning in the late 50s.
The engine itself would be easier to date based on the headlight and smoke box front details, the pilot stanchions, and the side rods and valve gear finish.
Here is an early 50s box. I don't think the 7-54 refers to a date, since the box came with a '51 Berkshire. I'm fairly certain (but not 100% positively sure) it was original to that engine.
Jim