These projects do not start with assembly. They start with machine code interleaved with data. Even getting to assembly through a disassembled requires some input and understanding. Usually these are raw binaries with no (or limited) metadata.

When run through a disassembler, in most cases, it’s probably the first time anyone has ever looked at the assembly (assuming PlayStation or newer). There are no comments or labels or symbols. Not what most people would consider “the original assembly”.