When SPDY is available for a site, does Googlebot use it? If so, sites which are SPDY enabled would appear faster to Googlebot.
No, Googlebot doesn't use SPDY. SPDY was optimized for browsers, where things like pipelining & HTTP request headers are bottlenecks. These things generally aren't issues when crawling the web.
That said, SPDY may have some benefit in saving the server some work (it can serve multiple URLs with one request/response), so I wouldn't say that it's completely out of the question, but it's not used at the moment.