No, the API for Win32::IEAutomation is entirely different from Mechanize. And it hasn't been touched since 2007. I found a post from Gábor Szabó in 2006 asking about the differences between the two.
It's a mystery. There is unbelievable cruft in CPAN going back to the last century, and yet people seem to use Win32::IE::Mechanize and it's dropped.