After writing the last blog, I did some more Googling and found a few site dedicated to LDAP attributes:
(For some reason, the last time I visited support.microsoft.com and searched for LDAP info, all links were dead. It was the same day Bill Gates announced he would, in two years, step down from running Microsoft to dedicating himself to giving away his ill-gotten wealth, maybe it was all related...)
Nice Excel table listing all attributes, but many attributes have no associated descriptions.
Both locations list the creator attribute as an indicator of who created the object. Strangely, plugging the attribute into my script yielded nothing. I wonder if it's because we created AD accounts via NetIQ DRA and not directly through Computer Management or similar built-in tool.