I've heard that, ever since the pro peloton switched to 11 speed rear cassettes, a largest sprocket size of 28 is pretty common. In the mountains, some teams even switch to 32. 11 as the smallest size is super standard. The big news on Sunday was that Greipel's bike had a malfunction and could only go to the second smallest cog (12 tooth).
52/38 front sprockets aren't standard for consumers (they are usually 53/39 or 50/34), but the pro teams have mechanics who take apart the bike every stage anyway and will install non-standard sizes.
As for the rear cassette, an off-the-shelf 11 speed cassette from 11-28 has the following number of teeth: 11-12-13-14-15-17-19-21-23-25-28 (source:
http://www.bike24.com/p259218.html)
Of course, the pros can switch the sprockets to any size they want.