Old key reinstall WITH SP1?

I was wondering on the page win7 activation errors (http://windows.microsoft.com/en-US/windows7/Windows-7-activation-error-invalid-product-key) it says "You can't use a product key for Windows 7 with Service Pack 1 (SP1) to activate a copy of Windows 7 without SP1." I was wondering if it is possible to do the opposite though; To reinstall windows with sp1 using a product key that came...