I wish I could answer that but if it was part of the reasoning for the alteration... it was a failure... because the uneven reduction the height of the lug (what I'm calling the portion that enters the frame hole) in addition to everything else you see in the photos, it sits too low and now does rub the frame, and has left some light scratch marks.

I am clueless as to the reasoning behind this alteration although mention has been made in a previous post that it can enhance the action, but other than the Jerry Miculek "Trigger Job" DVD that was referred to, that I have not seen... I am unaware how it could be of benefit.

What I see as being the most odd aspect is this is a little to no use gun that shows no signs of ever being worked on outside of the factory build. I don't mind replacing the part but it is hard to find and from what I have discovered from what is available are mostly used and expensive thumbpieces for this gun.