You're probably right that it hasn't been changed. With all your time invested in this, you're clearly one of the gurus when it comes to these wiring harnesses! Is there a way to visually tell whether it's been changed or not? Is there a tag on the harness somewhere with a part number?
Once I can determine with certainty whether it's been changed I'll be able to relax about it. I want to know so that I'll have an idea of potential problems for the future.
Thanks for the help, and please let everybody know how your wiring issue turns out. Is your car drivable in the meantime?
Experience is something you don't get until just after you need it.