The trend in law enforcement weapons over the past 20 years has been to gun with as few controls as possible. Most/All of the new duty type guns have no safety, for example to S&W M&P, Kimber, SA XD, ect. I really don't see Glock adding one to all of their guns just for the heck of it.
Yes, if the military wants it and is going to buy enough guns and parts, I could see Glock adding it to those guns or that specific model.
If the gun is neat enough and considerably different than there current offerings, even all of us Glock Safety haters will buy one.
Steve