Along the way, a number of model kits were discovered that contributed parts to the gun. I own two of them, and the third finally showed up today. It's the Kazon ship from Voyager. Interesting enough, this model kit was also the foundation for a few hand props seen in Voyager and later on Enterprise. The Hirojin hand phaser was created using this kit, which was later modified into the Vulcan pistol used in Enterprise. Craziness!
Here you can see the two pieces that are used on the ZF-1. They are sort of like covers for hose entry points into the scope cup.
And with the arrival of this kit, I now have everything I need to make the scope cup. I'm almost done assembling it, and will be molding it and offering castings. Drop me a line if you are interested in a set.