There is no pin in the new ILS mainspring housing. The key lock of the ILS takes the place of the pin.
I did not like the heavy trigger , the arched mainspring housing, nor the ILS gizmo, so the first thing I replaced on my Springfield Mil-spec was the mainspring housing, and had to also buy a mainspring, mainspring cap, and the pin. None of the ILS parts will function properly in a standard 1911 housing. After replacing with parts and springs from Wilson, a new 4 leaf sear sping from Brownells, trigger pull was drastically reduced, and now is a shooter I love.