After going through some of the stuff I've accumulated, I think this might actually be the GYOW b-side version of SS. It's about a minute and a half shorter than the expanded Rumours version, and I think it might be the same one from The Chain box set.
I don't think I'm breaking any copyright laws, seeing as how this version isn't commercially available anywhere else as far as I know and the box set is out of print.
http://www.sendspace.com/file/l5fykw
This is turning into the definitive Silver Springs thread
Anyone else have any versions they wanna contribute?