There are a lot of moving parts in the auto version's trigger pack.
Very interesting. Some of the stuff is pretty obvious how it works and not very different from other autos, like the sear trip (55), but there are some weird parts in there, specifically part numbers 50 and 53. What does a "hammer lever pin" do? Part 59 is a weird one, too.
Looks like every part in the trigger pack is different, to include the metal trigger case. I would not be surprised if the plastic housing and receiver are also different. The bolt probably also has a ramp to trip part number 55, though the ramp isn't visible in the drawing.