AR-15 Hammer and Trigger Large and Small Pins
Some civilian Colt AR type rifles were manufactured with hammer and trigger pins and holes which are .170 inches in diameter. These are referred to as large pin Colt receivers. This was not in all Colt models, just some.
All other AR type rifle manufacturers have used the military specification .154" diameter hammer and trigger pins and holes, or small pin.
The only way to know for sure is to measure your pins or the holes in your lower receiver to determine if you have a small pin or large pin Colt receiver.