Yes, you are correct. The last upgrade for Mk3 is 3/1-63 so if you have the v31 mode2-form1 burned in slow speed and the key CD, you should be good to go. The update process if very simple:
1. Put the key into postion1
2. Eject Map CD and put in the software CD
3. Follow instructions on the screen

After you installed the update you should get the split screen option under Settings.