Howdy: Yep, the 'Springer' was the easy part but I would have gone 'Huh' with the 'ignition system' lingo myself (like, when did 1911's start using spark plugs, huh?).
The gizzy I call a sear plunger is, by whatever name it is properly termed, that little part that sticks up through the frame and portrudes into the cutout in the bottom of the slide about halfway between the boltface and the hammer notch. When that plunger is 'up', you can pull the trigger, engage the sear and the hammer will drop. When that plunger is depressed, you can't.
I understand that the Colt WWII 1911 repros do not have the series 80 trigger/hammer/sear block, so the trigger pull can be improved. For my GC, when I saw the narrow sear the GC was using I replaced it with a full sized Chip McCormick sear and plunger and my trigger pull was very, very nice.
Hope this helps. Mikey.