In this Shot Show video, the S&W rep says they changed the footprint on the new 30 Super Carry Shield Plus to accommodate the Holosun K footprint from the factory. He goes on to say something about hoping this will extend into the rest of the Shield Plus lineup eventually.
This may be doubly interesting for people looking at the new enclosed emitter K footprint optics from Holosun. It seems that direct mount is preferable to plates, and the heavier the optic the more important it may be.
Attempting to link video at relevant timestamp. Edit to add: Didn't work, time = about 4:30