Real 1911, 1911A1 and commercial Colt Government Models were built in an environment where there were recognized material, processing and manufacturing standards as well as dimensional ones.
Today there are none, and sometimes it shows.
There are uncounted manufacturers making copies of the genuine article that have little but a passing acquaintance with it. Any adherence to the old blueprint requirements is purely accidental. Some manufacturers don’t make anything at all. They buy all of the parts and simply assemble them into pistols that may or may not function.
Parts may be made from forgings, investment castings, molded or formed using MIM or punch press technology, or machined from bar stock. Materials include various alloys of high carbon or stainless steel, different kinds of aluminum, and even plastic (trigger fingerpieces and mainspring housings). To the degree that there are standards, each manufacturer makes they’re own.
The government drawings are interesting, but hardly relevant for any use concerning current pistols now being made; because no authority forces the various makers of components or pistols to conform to them, and as a result few or none do.
The most obvious difference between the genuine guns, and what are being made now, is that they worked out-of-the-box, without any tinkering, breaking in, substitution of after-market parts or magazines, special lubricants (whatever); and they did so on a predictable, consistent basis.