Oooo! You even have the arm hook! There's a lot of good info on here. By the way, just invade you don't know, DO NOT USE THAT PADDLE SAFETY! It was a faulty design and could fire when toggling the safety on and off.
http://www.youtube.com/playlist?list=PLQ_rWm8ki7vx_JKhGbgPT7WTpKpIbRoGS