Magazine follower button missing. S&W service rep advised it was left out deliberately. I asked for replacement buttons. She said they had none and to contact Magpul, their supplier. Had to talk to a supervisor, but they are shipping me 2 buttons. There are 2 was to install said buttons. In a free state, remove the pin blocking the follower and lower the follower all the way and the button will pop in. In a slave state, remove the follower and spring, drill a 3/8 inch hole through the mag body just above the pin and centered on the vertical opening, reinstall the spring, follower and buttplate, then install the button. You are simply duplicating the hole at the bottom of the vertical opening just above the pin. The supervisor advised me that the buttons were in stock and that I should have them in 2 weeks.