^^^^^Yup, What James said!
If the plunger tube is off and the grip bushings aren't installed, the 1911
frame is a big flat surface on both sides. From a manufacturing
standpoint---especially 100+ years ago---that is a huge advantage
in terms of machining time. I've made metal chips for a living for
years, and I really enjoy "reverse engineering" old guns. Trying to
figure out how they did that with 19th century technology.
