I stand corrected!!!
The reinforced pins are the best thing going for a 9MM rifle, due to the bolt being a blow back design and can reach havoc on the hammer pin/receiver during unlock. But on the 5.56 rifle, with a gas action that softens the carrier unlock, they are not needed.
If the hammer is not drilled for the retaining spring, then what does the kit come with to retain the pin, or is the intent to just replace the standard pins with a secondary system such as c-clip style or end screw type?
Don't get me wrong; it's just a question.
I have been working over stock FCG systems for so long that it has been several years that I have even used an aftermarket system, and that was a Jewel that was sold off shortly after I installed it in one of my DCM rigs (don't care for two stage triggers, only tolerate them on M1a's and Garands).