Yea, that doesn't sound right.
Can you give a little more detail on what's happening?
Um, I might just be stupid I guess. I saw "if you're not using Omnigraffle 6" and took that to mean "If you're not using omnigraffle at all", so then I expected it to be a folder of assets. So if I open the zip file, there's a single folder with 4 images and a plist. I assume that on a mac the .gstencil would open in Omnigraffle, whereas in windows it just opens as a folder.
Anyhow, just operator error I'm sure.
Ahh yes, that is partly my fault. I should've been a bit more clear. The .gstencil is for versions of omnigraffle prior to 6.
Sorry for the confusion.
You can download a trial of omnigraffle 6 and then export the stencil as an .svg
Edit: Scratch that. All I see is 4 images in both zip files... I'm confused.