CSS3 vs. Windows 7 Native Form Buttons

A study in the capabilities of CSS3 to replicate buttons in the style of Windows 7's native form buttons. Can you tell which is which?

This may not ever make it to production, as I don't feel great about serving Windows-looking buttons to all users, but I was curious how possible it was.

(Serving native buttons to each OS/browser is not possible, because our third party provider overrode the button styling, and so I'm forced to override that. There is no way to override it to the native styling.)