I just got a good deal on a used M&P9 fs, and would like to add a thumb safety to it if I can. I already have a compact with the safety, so I am familiar with the parts involved, and how they are installed. I know where to get all the parts.
The FS is from before S&W started including the safety cutouts on all the frames, so I know that I will need to cut those, and I'm ok with that part. My question is... The gun has (or at least had) an integrated lock. Does anyone know if the hole for the lock will interfere with cutting the holes for the thumb safety?