I'll add to that by saying that Colt used to sell two different types of hammers. One with a "captive" half cock notch, for Series 70 pistols and another type with a non-captive half cock ledge, for the Series 80 pistols.
They seem to have stopped doing this for a few years now.
...are different from the Series 70 and earlier. The Series 80 hammer has no half-cock, but is interchangeable with the earlier version.
The Series 80 Firing Pin is also different. It is backward compatible and will function normally. The earlier firing pins will not work in a Series 80 pistol, unless you remove the plunger. I'll leave a discussion of the merits of disabling safety devices to others.:mummy: