arstechnica.com/microsoft/news/2009/07/first-screenshots-of-windows-7-build-7600-leak.ars

"Reports across the Web are pointing to a build 7600 for both Windows 7 and Windows Server 2008 R2. This is significant because the bump in the build number would suggest that Microsoft has christened this build as the Release to Manufacturing (RTM) build. The RTM is expected to be given out to Microsoft partners sometime later this month and launched on October 22, 2009, the day General Availability (GA)."