First, thanks to all who responded. It is greatly appreciated.
Yes, I removed the windage screw from the original sight and transferred it to the HD rear sight.
The spring and plunger went "kazing" when I attempted to depress it to install the new sight. After multiple failures to get the plunger to "click" into place, it shot off into orbit. Yes, the HD sight requires the use of the spring and plunger.
Any additional tricks or suggestions would be appreciated. Next on the list is to contact Walther for a replacement plunger and spring.
Again, thank you, thank you.
..........................When relocating the factory sight windage screw into the new Trijicon, it does not fit "flush" with the sight. Is this a problem?