They're all the same size in terms of being N-Frames as opposed to K or L Frames, but there are small dimensional differences here & there, along with generational changes that have occurred along the way.

Swapping any given barrel from any N-Frame era into another of a different era may or may not work well.

While retaining the same overall size, N-Frames have evolved over the decades like the other Smith revolvers that have co-existed with them.
Denis