Yes, the series 7 50ae and newer models have the wider slide.
So you need a series 7 barrel to go with the series 7 slide (44 through 357).
As for the series 7 50ae, since the barrel had to be bigger, it used the wider slide, and to allow all the pistols to be barrel swappable, the new series used the new wider slide for all models (read with the new thicker barrels to go with the wider slide).