To start with here’s the info from the right of this plugin’s page.
Requires WordPress Version: 2.2.2 or higher
Compatible up to: 2.3
Last Updated: 2007-10-30
Well going on that info, I’d say that the one you’re referring to is probably newer and has either no relation or is a derivative of this one.
Also, when make accusation like that it is usually procedure to provide a link to other one that this, according to you, is a “copy” of otherwise no one can verify your claim.