Perfect parts! - Zaffiri Precision Glock 19 Gen 1-3 Upper Parts Kit

My ZEV (Zaffiri) Glock 19 Gen 1-3 Upper Parts Kit arrived, packaged in a small, protective plastic envelope that listed all part contents and had a clear window to see what was inside. I was pleasantly surprised that some of the sub-assemblies were pre-assembled (firing pin with retaining cups and spring, and safety rod, retainer and spring.) This saved a few minutes. I had purchased this parts kit to install on a ZEV slide (came with firing pin channel liner, pre-installed), with a ZEV barrel, for optimal compatibility. The parts fit the slide perfectly with no need to do any tinkering, whatsoever. Placing the slide on my Gen 3 frame, I found operation to be flawless on the first dry rack and fire, and during subsequent dry firing. Next comes the range trials, which I expect to go just fine.