I personally replace the factory sights with an RDS, it's all personal preference.
I'm guessing the white dot sight you have on the rear of the gun is just sitting there to see if you like the look.
I can see it's not mounted.
Like I said sites are just personal preference.
If you want to put on an RDS, I suggest primary machines do the Milling on on the slide, and install you're RDS. Mine is a vortex Viper Works terrific sits low.