The version of GSS that is compatible with Windows 7 is 2.5.1.2266
If you have an earlier build of 2.5 then you can run LiveUpdate to bring it up to the latest version available.
From the perspective of Windows 7 imaging, do you have a KMS server or a volume MAK key? If not, the images will lose their activation when deployed to different hardware, even if it is the same model.