I was recently lucky enough to grab one of the few Z-Grips that AGD found and sold at the online store. When it came, it had a safety, but the ball bearing, spring, and set screw were never installed. I have the parts...now how do I put them in? Do I have to remove the trigger to take the safety out and put the bb in the from the bottom, or can I drop all three in from the top? Thanks for the help-