This according to an email I received this morning from Smith & Wesson:
Unfortunately retrofitting the M&P is not possible at this time.
Frank Branchesi (from S&W)
-----Original Message-----
From: Craig
Sent: Tuesday, January 20, 2009 12:55 PM
To: Smith & Wesson Support
Subject: M&P9c
Hello,
I recently purchased a new M&P9c. I do like the pistol but this is my first striker fired pistol of my own. I see that you have introduced versions of your M&P's that have optional thumb safeties. Is this something that I could have retro-fitted to my compact 9mm M&P? While I like the gun, I would really like to have the safety on my gun.
Thank you for your help.
Sincerely,
Craig