Stuff you will need to switch out that ILS:
-a new mainspring housing, obviously
-a new mainspring, Officer's ACP length
-a new mainspring cap, mainspring housing retainer pin (both in Officer's ACP size, which is larger in diameter)
-a new mainspring cap pin
The fire control parts for a trigger job, such as the hammer, disconnector, and sear, sear spring, and trigger are all the same as any other 1911, with the exception of a Colt Gold Cup.