I sort of expected to see some questions about whether the dot sight should be behind the rear iron sight or in front of it.
Like many people, I thought the iron sight being in front of the dot sight "looked funny" and was unsure about how well it would work (since most every other gun has them reversed).
After having two done that way I'm fine with it.
Some people say, "oh, but the iron sight in front of the dot sight obscures the sight picture." Think about it. If the iron sight is tall enough to actually serve it's purpose its the same height, in front or behind and obscures the same amount of the target/dot lens.
I think it does provide an advantage, but can't say how much. There's a good chance, that any piece of brass, or fragment of powder residue that may come out of the ejection port is likely to hit the rear sight first and be deflected away from the dot sight lens.