I would say there would be many ways to do this,
1) If you have the details actually printed in the PDF use a keyword test to open the PDF, have TestComplete take a screenshot, use an image mask on everything but the date and time area that you want to test for.
2) use a keyword test to open the file properties in windows File Explorer ( I believe it is \windows\explorer.exe on my 32-bit windows 8.1) again TestComplete Screenshot the Details window and use mask what you do not want to test here.
3) script test to get the file date and time stamp - I think it is very simple to get that information.
4) if you have the PDF save to a specific folder that you empty often and should be the only file there use keyword test to open file explorer to the folder, set the folder to view details, have the keyword test log the on screen element of date/time for the file.
There are probably many others but that's some that I just thought of after reading your post. Have a good weekend.