well...depends on the company providing the budget and the developers for ex, Hideo Kojima bases some of his weapons off of actual military artillary (I read that one month on PSM on a big special about MGS2; really interesting)
wouldn't make a difference anyway parents are usually the ones who buy the video games anyway sometimes the clerks don't care about your age anyway shiit, at Toys R' Us they sold my brother RE: Director's Cut when he turned 9