Find the Date - File Info
For documents like PDF, PPT, JPG and others, it is possible to find the date they were created or last modified by downloading them and looking in PROPERTIES.
For example, open the PDF in the example below. Download it--it may then prompt you to save it or open with Acrobat. Choose to open it. With the document open, click FILE and choose PROPERTIES. Find the MODIFIED date and paste it in the box below. PDF Example