Here are a couple pictures of my 1991A1 project. Alan Tanaka did the machining and bead blasted the parts for me. I did the Parkerizing with Palmetto Manganese Phosphate.
The Parkerizing is darker on the slide and hammer than the frame. It is different as I understand from the steel alloy being different. I lowered the hammer hooks to .025 which gave a clean break at 4.5 pounds.
Nice pistol - Clean and crisp with no unpleasant aftertaste! It always surprises me how much color variation you get between different parts when they are parkerized.
The trigger is from EGW, I had read good reports about a flat trigger from Hilton Yam and thought that I would try this one. The appearance is a little different, but it feels fine. I had no problem with the change. If you have a large hand span it feels perfect.