Which Arduino pins are used?

I got the Motor Shield version 1 from Radio Shack. The documentation is not clear on exactly which Arduino I/O pins are claimed by the shield. I need to know what I/O pins I can use for other purposes. If I understand correctly only Arduino pins 8 through 13 are used by the shield. Therefore, I would be free to use all of Port D of the microcontroller (Arduino Digital pins 0 through 7) as well as Analog Inputs A0 through A5 for other purposes.
The Motor Shield doesn’t have stacking headers so it seems that to access those other pins I would have to make my own shield between the Arduino and the Motor Shield unless there is some Grove adapter jumper for connecting to male headers on another board. If there is such an adapter, which Grove headers do I use? I don’t see any documentation for this.