BDG: No, there were no wear marks on my trigger bar's sides. When I realized the smooth appearance was the rust preventive coating, I got curious about it and stoned the sides. This revealed tool marks, but not bad at all.
And thank you so much for your excellent post and photos. There aren't many of the decocker sear cage assembly, and yours was very useful as I smoothed my PCR and installed the 3-spring kit.
Reassembly has been difficult, but educational. I've had to make up a firing pin block spring (part #15) to replace the one that slipped off into the night. At least it's the simplest spring in the gun.