is there any way to find out which version of PADS a design was created in? E.g version 2007.2, 2007.4, 9.3.1 etc.
Yes. Export the design in ascii. Then open the asc file with a text editor. The first line of text tells you the PADs revision number
But wouldn't that just reflect the current version of the program used to open and export the file, and not the original version which created the file?
Yes, you have a point there. Then the only place the revision info would be stored would be in the pcb file. This is a binary file that can't be opened with a text editor. I'll bet if you open it in a hex editor you'd see the version info.
Retrieving data ...