Gotcha! I hadn't realized that Worldcat is NOT a plugin/option that you can manually adjust. I figured I'd at least get most of the dates right if I found a good source (& adjusted the settings just right) and have to change only some.
So what IS the point of giving us the option to check/uncheck whether we wanna download the "published date" from a certain source if Calibre is just gonna do their own collation process... I understand the whole concept of "Utilitarianism" (do the most good for the most people), which is what their collation process probably does, but it'd be nice to have the option to turn that off for the more "OCD" people who want to perform a much more customized process...
I had already accepted that I wasn't gonna be able to automate the process... but I was hoping to get at least 80% of the way there