If it has been released, why hasn't Microsoft said so? Normally they announce things the minute the final build has rolled off the metaphorical tongue of the servers.
With Windows 7 still in the process of development and marketing campaigns, surely the IE8 release for XP, Vista and Windows Server will be older than the one in the final released Windows 7?
The EU have spat the dummy out in regards to the antitrust issues with Internet Explorer, so surely this will screw things up in both releases.
The recent release candidate version of the software doesn't work on Windows 7, making me think a special semi-integrated version will be rolled out for the next version of Windows. If this is the case, you can hardly call any build at the moment which is incompatible with Windows 7 as a "final" product.
The announcement of a new reliability update for Windows 7's in-built version of IE8 also caught my attention. If they're still releasing updates for a finished product, the product isn't finished. The time stamp on this post on the IEBlog suggests updates are still being rolled out for the beta product, and that the final release will probably still be on course for next month.
Maybe I'm rambling, either way - just a thought.