Thanks for the comments. I shipped the Glock to Rick Devoid of Tarnhelm Supply in NH. I will do a follow up post when I receive it back from Rick.
As to why I wanted a manual safety. I carry IWB using a Clipdraw (there is an ongoing thread regarding that subject in Carry Issues Section) and was using the Saf T Blok trigger block behind the trigger. It functions as it should but is an external part that can be dislodged or lost. And it is hard to practice with because you have to look for it after every course of fire. I am accustom to a manual thumb safety and that is all (IMO) the Glock needed to meet my needs.
[URL="http://www.Glockstore.com"]www.Glockstore.com[/URL] to see the Saf T Blok