There are definitely different versions of the DE2 board. I think there may be different hardware revisions of the board with the Cyclone II (EP2C35F672C6), and there are versions of the board with larger FPGAs (the DE2-70 and DE2-115).
Here's the pin assignments script I use for my Cyclone II DE2 board. You could compare it to yours and see if there is a difference.
Have you looked on Terasic's web site for details? I have an archive of old Terasic zips/CDROM images on hard-drive at work. I can send the schematic for this board if you wanted it.
Cheers,
Dave