That would be correct, 2 for serial and 2 for power, and just tie the two grounds together.
if you dont ground the serial line you will be tearing your hair out trying to figure out why it wont send any data :)
Here is mine,
i'm actually using 5 wires because my antenna takes 5 volts instead of 3
also when you get it installed, make sure you try turning on all the sentences on (the default is only like 4 of them) I want to see if that fixes the mouse jumping issue