I got that "idea" from your first sentence of your first post......its is NOT installed after the gun is blued......
the 'cross pin that goes across the rear of the frame is what holds the busing in place, not the firing pin ,that goes in when the bushing is inserted, tapped or presssed into place, then the cross pin , the gun is polished and blued, blended in to the area above and below it in the rear sculpted area of the cylinder frame...... You stated that the ends of the cross pin were "in the white"???cannot be, and if the bushing sticks out or drags or rubs against anything to do with the cylinder, it gets polished, if its replaced it will be "in the white, same goes for the area off to either side of the recoil shield, may get filed, fitted....if all is smooth, and NO fitting required, this surface will be ALL blued, smooth, across the recoil shield...you can see the file marks in the picture above, we';ve seen a lot of them with NO marks or filing or fitting, all was OK when the gun was built took them a few years to get things down pat.........
and your statement as to the cylinder, above .same thing the ends are fitted ,filed to the gun AFTER it is blued, if it "drops in", no fitting, needed the ends could be blued., dark and only show some 'wear' from turning...........front AND rear of the cylinder.
it does not have to have been 'NIB' to have a "blued" firing pin bushing as this picture shows a OM ,used and the bushing is still blued......