The full build in no. of this SP is 7601.16556.100421-1510 as the build no. indicates it was compiled on 21st April 2010 at 1510 Hrs
As we all know Microsoft has already announced that Sp1 will not include any big change or any kind of visual changes it only comes with bug fixes and patches.
You can easily get this SP from any torrent site but as we always say PLEASE DON’T DOWNLOAD THESES LEAKED VERSION BECAUSE IT MAY COMES WITH MALWARE OR ADWARES.Wait a little bit for the official release of it.As the news coming Microsoft may release the RTM of Windows 7 Sp 1 in October Or November 2010.