Generally the side that they come from is the side that you place them back into. PROBLEM: I can never remember which way. For my Savage rifles I THINK one removes from right (right hand trigger finger side) to left, and replace from left to right but it's been a while since I've done it. Wait for an H&K expert to tell you for sure. I had my gunsmith do my H&K years ago because he had the sight puller....cost me $10.