Unless you can compare it to an original copy, no. While the document properties will show you basic stuff like the last modification date of the file and which application wrote it, all that data can be faked and of course only means something if you know what it's supposed to say.
Thank you DAVE ,
What do you mean by " supposed to say" & don't you think a computer expert could discover the fake ?
I mean that if you know the file should have been last modified on May 3 2009 (because you asked the guy who made it) then you can see if it's different - but anyone can change that date, forward or backward.
There is no version-tracking data within a PDF file, so even we can't tell if a file has been messed about with unless the editor chooses to leave something obvious, like a change in date or a note in the document properties.
The best way to ensure a file hasn't been messed with is to digitally sign it. The signature is automatically removed when the file is modified.