A user by the name of sp3ciali5t has managed to post an image of the IE9 about screen for this build on Twitter. It's in Turkish, but you can still see the build number:
Earlier this week, Microsoft confirmed that IE9 would be launching on March 14, 2011 at 9:00 AM PST. The company will hold a launch party in Austin, Texas during the South by Southwest Interactive Festival (SXSWi), but not before a press briefing where IE senior director Ryan Gavin said there will still be "a few surprises."
Microsoft unveiled the first IE9 public preview in March 2010. This was followed by multiple further public previews as well as a public beta in September 2010. Last month, Microsoft released a public IE9 Release Candidate build.
IE9 will be available in 32-bit and 64-bit flavors for Windows Vista and Windows 7. Users of Windows XP will thus not be able to upgrade past IE8.