Which turn signal kit to use?

[John Walters]

I have a 30 Pickup, with two tail lights, want to add turn signals to rear. Mac's has a "lighting wire harness-with built-in turn signal wiring-without cowl lamps-for 2 bulb system". Is this what I need? Do I have to add turn signals to front, or can I do it to rear only with this kit? Please clarify "2 bulb system"

Thanks.