“… (by Chris Schweiter)
It looks like the true source code was chewed by some kind of preprocessor before being dumped into the resource files that the game uses. Ken, you helped write the AGI interpreter in the first place. Is there any truth to this?…”
Yes — the code was run through a compiler, and compiled to an intermediate language. You cannot get back to the original source code. My guess is that it has been lost forever. I doubt Sierra was organized enough to preserve it.