cpollett - 4:30 pm on Dec 12, 2012 (gmt 0)

I wasn't sure if your were interested in setting meta information about the PDF or if you wanted something that allowed you control of a robot similar to the meta robots tag for html. If its the latter, then you may want to consider x-robots-tag http headers:

https://developers.google.com/webmasters/control-crawl-index/docs/robots_meta_tag