The only issue that may create an incompatibility seems to be the IOREF pin next the 5V output pin which is extra on Revision 3 but not in Revision 2.
However, I just had a look at the board schematics and the shield does not use IOREF.
Pin 2 is extending IOREF
So, the shield should work correctly with the Uno Revision 2. As far as the extra pins are concerned, I would recommend not damaging them in any way. If you absolutely need to, then just try to bend them outwards very carefully.