Brian Freiesleben notified me that Google is now showing thumbnails of the PDF document in the mobile search results. Here is a screen shot I was able to replicate myself, that shows a screen shot of one of the pages of the PDF document Google lists here in the search results.
Brian shared this with me on Twitter and although it seems like I have seen this before, I really cannot find myself covering it anywhere. We do know Google can show an image in the search results from a PDF document. But this is different.
Forum discussion at Twitter.