How do you not have a gas block? Is it one of those NY state legal pump AR15s?
It has a gas block, it is just under the hand guard. The barrel is free floated.
I don't believe there is a way to add sights to this model easily. I do not have one, but from what I can tell from pics, it doesn't look like there is a way to attach a piece of rail to the hand guard without some modification.