I doubt it. I don't see how it could make the slide stop drop, especially when pressing the stop downward (when adjusted) will do the job just fine.

I have not seen any discussion of it either, but my guess is it might be a guide/support for the rather long arm of the stop to keep it from flexing. I would not be surprised to find one on the opposite side of the gun too, but I have yet to find a photo of the right side.

I guess we'll know soon enough as the actual guns are purchased and examined.