So I'm thinking about getting my first AR-15 and I've decided on the stag model 7. The question I have is am I good to go as long as I have a bullet button on it? I've done massive research and it seems that as long as that is installed I'm good to go? I found a place in southern California that does modifications to make them CA compliant. Also, any thoughts on the model 7? All the reviews seem to be that it's a consistent out of the box 1/2 moa performer.