One thing I've noticed with just handling the 407K around the house, it definitely has a "fishbowl" effect to it. I don't necessarily think it's magnification, but more of a distortion. I noticed that slightly with my first gen HS407C sights, but not really seeing that with the gen 2 that I have. Just thought I'd mention that. Time will tell if that actually causes me any issues in the long run.
I have heard others mention this. I have to look for it to see it and never notice it while actually shooting. Could be slightly different on mine or I just see slightly different.