The smoothing issues I've seen plenty of times before, might have something to do with not using the specular maps that are also designed for it. Problem with that is that most people use icenhancers, and with that they'll turn really shiny (almost mirror-like) if you use specular maps. I can mount on a different eotech but I don't know how much that'll do, I'll also mount the front iron sights on the rail.
Purple spots shouldn't be visible, the only thing I can imagine being the cause of that are the normal maps which are only intended for lighting. So maybe if you have a certain graphics mod installed it's causing this error